Tropical Dermatology — MCQs

Q: Which of the following conditions is characterized by the sign of the groove?

Lymphogranuloma venereum. **Explanation:** **Lymphogranuloma venereum (LGV)** is caused by the **L1, L2, and L3 serovars of *Chlamydia trachomatis***. The "Sign of the Groove" (Greenblatt’s sign) is a pathognomonic clinical finding in the secondary stage of LGV. It occurs when the inguinal and femoral lymph nodes enlarge simultaneously, separated by the rigid **inguinal ligament**. This creates a visible depression or "groove" between the two groups of inflamed lymph nodes. **Analysis of Incorrect Options:** * **B. Granuloma Inguinale (Donovanosis):** Caused by *Klebsiella granulomatis*. It presents with painless, beefy-red, velvety ulcers. It is characterized by "pseudobuboes" (subcutaneous granulation tissue) rather than true lymphadenopathy. * **C. Syphilis:** Primary syphilis presents with a painless, indurated "hard chancre." While it causes bilateral inguinal lymphadenopathy, the nodes are discrete, rubbery, and do not form a groove. * **D. Chancroid:** Caused by *Haemophilus ducreyi*. It presents with painful, soft ulcers and painful inflammatory buboes that are usually unilateral and may suppurate, but they do not form the characteristic groove sign. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of LGV:** Primary (painless papule/ulcer), Secondary (Inguinal syndrome with the Groove sign), and Tertiary (Genito-anorectal syndrome/Elephantiasis). * **Diagnosis:** Frei test (historical), NAAT (current gold standard), and **Donovan bodies** (safety-pin appearance) are seen in Donovanosis, NOT LGV. * **Treatment:** Doxycycline (100 mg BID for 21 days) is the drug of choice for LGV.

Q: A young tourist presents with an erythematous lesion on the cheek with central crusting after visiting a region endemic for a specific protozoal infection. What is the likely dermatological condition?

Cutaneous Leishmaniasis. ### Explanation **Correct Option: A. Cutaneous Leishmaniasis** Cutaneous Leishmaniasis (CL), often referred to as "Oriental Sore" or "Delhi Boil," is caused by the protozoan *Leishmania* species and transmitted by the bite of an infected **female sandfly (*Phlebotomus*)**. The classic presentation begins as a small erythematous papule at the inoculation site (usually exposed areas like the face), which evolves into a nodule and eventually develops **central crusting** or ulceration with a raised, indurated border. The history of travel to an endemic region is a crucial diagnostic clue. **Why Incorrect Options are Wrong:** * **B. Systemic Lupus Erythematosus (SLE):** Typically presents with a "malar rash" (butterfly distribution) that spares the nasolabial folds. It is an autoimmune condition, not associated with travel to protozoal endemic areas or central crusting. * **C. Lupus Vulgaris:** This is a chronic form of cutaneous tuberculosis. While it affects the face, it typically presents as "apple-jelly" nodules on diascopy and follows a very chronic, progressive course rather than an acute post-travel presentation. * **D. Chilblains (Pernio):** An inflammatory response to cold, damp conditions. It presents as itchy, purple-red bumps on fingers or toes, not as a crusted facial lesion following tropical travel. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** Female Sandfly (*Phlebotomus*). * **Diagnosis:** Skin biopsy or slit-skin smear showing **LD bodies** (Leishman-Donovan bodies) within macrophages. * **Treatment of Choice:** Intralesional or systemic **Sodium Stibogluconate** (Pentavalent antimonials) or Miltefosine. * **Volcano Sign:** The appearance of a crusted ulcer with a central pit is often described as the "volcano sign."

Q: A child from Bihar presents with hypopigmented patches on the face. What is the most likely diagnosis?

Leprosy. **Explanation:** In the context of NEET-PG, the geographical location provided in a clinical stem is a critical diagnostic clue. **Bihar** is a highly endemic region for **Leprosy (Hansen’s Disease)** in India. In an endemic area, any hypopigmented patch in a child should be considered Leprosy until proven otherwise. The diagnosis is clinically supported by the presence of sensory loss (anesthesia/hypoesthesia) within the patch and/or thickened peripheral nerves. **Analysis of Options:** * **Leprosy (Correct):** The most common presentation in children is a solitary, ill-defined hypopigmented patch (Tuberculoid or Indeterminate spectrum). The epidemiological link to Bihar makes this the most likely diagnosis for exam purposes. * **Pityriasis alba:** This also presents as hypopigmented patches on the face of children, often associated with atopy. However, the patches usually have fine scaling and lack the sensory loss or nerve involvement characteristic of Leprosy. * **Vitiligo:** This presents as "depigmented" (chalky white) macules rather than "hypopigmented" patches. The borders are usually well-defined, and sensation remains intact. **Clinical Pearls for NEET-PG:** * **Cardinal Signs of Leprosy:** 1. Hypopigmented/erythematous patches with definite loss of sensation. 2. Thickened/tender peripheral nerves. 3. Positive skin smear for Acid Fast Bacilli (*M. leprae*). * **Differential Diagnosis:** For a hypopigmented patch on the face, always consider *Pityriasis versicolor* (fungal, "spaghetti and meatballs" appearance on KOH) and *Post-inflammatory hypopigmentation*. * **High-Yield Fact:** The most common nerve involved in Leprosy is the **Ulnar nerve**, but the most common nerve involved in the face is the **Zygomatic branch of the Facial nerve** (leading to lagophthalmos).

Q: What is the early reaction of the Lepromin test known as?

Fernandez reaction. The **Lepromin test** is a skin test used to measure the cell-mediated immunity (CMI) of a patient against *Mycobacterium leprae*. It is not a diagnostic test for leprosy but is used for classification and prognosis. ### Explanation of the Correct Answer The **Fernandez reaction** is the **early reaction** observed in the Lepromin test. It occurs **48 to 72 hours** after the intradermal injection of lepromin. It is a Type IV (delayed-type) hypersensitivity reaction to the soluble bacterial proteins. A positive Fernandez reaction indicates that the individual has been previously sensitized to *M. leprae* antigens. ### Why Other Options are Incorrect * **Late Mitsuda reaction (Option A):** This is the **late reaction** observed **3 to 4 weeks** after the injection. It represents a granulomatous response to the bacillary components of the lepromin. It is highly positive in Tuberculoid leprosy (TT) and negative in Lepromatous leprosy (LL). * **Early Mitsuda reaction (Option C):** This is a misnomer. The Mitsuda reaction is inherently a late-phase reaction. * **First lepromin reaction (Option D):** This is not a standard medical term used to describe the phases of the Lepromin test. ### High-Yield Clinical Pearls for NEET-PG * **Prognostic Value:** A positive Mitsuda reaction indicates strong CMI and a better prognosis (Tuberculoid end of the spectrum). * **Classification:** Lepromin test is **Negative** in Lepromatous Leprosy (LL) due to anergy and **Positive** in Tuberculoid Leprosy (TT). * **Antigen Types:** * *Lepromin H (Hayashi):* Derived from human leproma. * *Lepromin A (Armadillo):* Derived from armadillo-grown bacilli (more commonly used today). * **Memory Aid:** **F**ernandez = **F**ast (48-72 hours); **M**itsuda = **M**onth (approx. 3-4 weeks).

Q: Which of the following are clinical features of Erythema nodosum leprosum?

Fever. **Erythema Nodosum Leprosum (ENL)**, also known as a **Type 2 Lepra Reaction**, is a systemic immune-complex mediated (Type III hypersensitivity) reaction occurring primarily in lepromatous (LL) and borderline lepromatous (BL) leprosy. ### **Explanation of Options** * **A. Fever (Correct):** ENL is a multi-systemic inflammatory syndrome. **Fever** is the most common and characteristic constitutional symptom, often accompanied by malaise and prostration. It signifies the acute systemic nature of the immune response against released *M. leprae* antigens. * **B. Hepatitis:** While ENL can cause multi-organ involvement (like nephritis or orchitis), clinically significant hepatitis is not a standard or defining feature of the reaction. * **C. Joint Pain:** Although arthralgia can occur in ENL, "Fever" is considered the hallmark systemic sign in standard medical examinations. In many MCQ formats, if forced to choose the most definitive systemic feature, fever takes precedence. * **D. Skin Eruptions:** While ENL presents with painful, evanescent subcutaneous nodules, the term "skin eruptions" is too non-specific. The question specifically tests the recognition of the **systemic** inflammatory markers of the reaction. ### **Clinical Pearls for NEET-PG** * **Mechanism:** Type III Hypersensitivity (Immune-complex deposition). * **Classic Presentation:** Tender, erythematous, evanescent (short-lived) nodules appearing in crops, usually on the pretibial surface and face. * **Associated Features:** Neuritis, dactylitis, iridocyclitis, orchitis, and lymphadenopathy. * **Drug of Choice:** **Thalidomide** is the most effective treatment for ENL. Prednisolone and Clofazimine are also used. * **Trigger:** Often precipitated by starting Multi-Drug Therapy (MDT), pregnancy, or stress.

Q: An 8-year-old boy presents with a white, non-anesthetic, non-scaly hypopigmented macule on his face. What is the likely diagnosis?

Indeterminate leprosy. ### Explanation The correct diagnosis is **Indeterminate Leprosy**. This is the earliest clinical stage of leprosy, often seen in children. It typically presents as a single, poorly defined, hypopigmented macule, most commonly on the face, extensor surfaces, or buttocks. **Why Indeterminate Leprosy is correct:** In the early stages of leprosy, nerve damage is not yet extensive. Therefore, the classic signs of leprosy—such as **anesthesia** (loss of sensation) and **anhidrosis** (loss of sweating)—are frequently **absent**. The presence of a non-anesthetic, non-scaly hypopigmented macule in an endemic area should always raise suspicion for indeterminate leprosy. **Why the other options are incorrect:** * **Pityriasis alba:** While it also presents as hypopigmented macules on the face of children, it is characterized by **fine, powdery scaling** and is often associated with atopic dermatitis. * **Pityriasis versicolor:** This fungal infection presents with **fine scaling** (demonstrated by the "coup d'ongle" or scratch sign) and typically affects the trunk rather than the face in children. * **Neuritic leprosy:** This form involves nerve trunks without any visible skin lesions. It presents with motor weakness, sensory loss, or nerve thickening, but not with a hypopigmented macule. **NEET-PG High-Yield Pearls:** * **Indeterminate Leprosy:** Most cases (approx. 75%) self-heal; others evolve into the polar forms (TT or LL) depending on the patient's cell-mediated immunity. * **Histopathology:** Shows a non-specific perivascular and periappendageal lymphocytic infiltrate. Acid-fast bacilli (AFB) are rarely found. * **Clinical Tip:** If a hypopigmented patch on a child's face is **non-scaly** and **non-itchy**, think Indeterminate Leprosy first in the Indian context.

Q: Which of the following is true for multibacillary leprosy?

All of the above. **Explanation:** Leprosy (Hansen’s Disease) is classified by the WHO into **Paucibacillary (PB)** and **Multibacillary (MB)** types based on clinical and bacteriological criteria to simplify field treatment. 1. **Option A (Lesion Count):** According to the WHO classification, patients with **more than 5 skin lesions** are categorized as Multibacillary. Additionally, if a skin smear is positive at any site (regardless of the number of lesions), the case is classified as MB. 2. **Option B (Clofazimine):** The standard WHO Multi-Drug Therapy (MDT) for MB leprosy consists of three drugs: **Rifampicin, Dapsone, and Clofazimine**. Clofazimine is crucial as it provides both bactericidal action and anti-inflammatory properties, which help in preventing Type 2 Lepra reactions (ENL). 3. **Option C (Duration):** The recommended duration for MB-MDT is **12 months** (12 blister packs to be completed within 18 months). In contrast, PB leprosy is treated for 6 months. Since all three statements accurately describe the management and classification of Multibacillary leprosy, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **MDT Regimen (MB):** Rifampicin (600mg once monthly), Clofazimine (300mg once monthly + 50mg daily), and Dapsone (100mg daily). * **Cardinal Signs:** Hypopigmented/reddish patches with loss of sensation, thickened peripheral nerves, and positive skin smears. * **Drug Side Effects:** Clofazimine causes brownish-black skin discoloration; Dapsone can cause hemolysis or "Dapsone Syndrome." * **Accompanied PB Criteria:** 1–5 lesions and no nerve/single nerve involvement.

Q: What is the drug of choice for Granuloma venereum?

Erythromycin. **Explanation:** **Granuloma venereum**, also known as **Donovanosis**, is a chronic, progressive bacterial infection of the genital and perianal regions caused by the Gram-negative intracellular organism *Klebsiella granulomatis* (formerly *Calymmatobacterium granulomatis*). **Why Erythromycin is the Correct Answer:** According to standard dermatological guidelines and traditional textbooks (like IADVL), **Erythromycin** (500 mg four times daily) is considered a primary drug of choice, particularly in pregnancy. However, it is important to note that modern CDC guidelines now recommend **Azithromycin** (1g weekly or 500mg daily) as the first-line treatment due to better compliance. In the context of this specific MCQ, Erythromycin remains the most appropriate choice among the provided options. **Why Other Options are Incorrect:** * **Sulfonamides:** These were used historically but are no longer preferred due to high rates of bacterial resistance and lower efficacy compared to macrolides. * **Streptomycin:** While effective, it requires intramuscular administration and carries risks of ototoxicity and nephrotoxicity, making it a second or third-line alternative. * **Penicillin:** *Klebsiella granulomatis* is inherently resistant to Penicillin; it is the drug of choice for Syphilis, not Donovanosis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Donovan Bodies:** Pathognomonic finding; these are safety-pin shaped organisms seen within large vacuolated macrophages on a **crush smear** (Giemsa or Wright stain). 2. **Clinical Presentation:** Characterized by **painless, beefy-red, velvety ulcers** that bleed easily on touch (friable). 3. **Pseudobubo:** It does not cause true lymphadenopathy; instead, it causes "pseudobuboes," which are subcutaneous granulomatous swellings in the inguinal region. 4. **Treatment Duration:** Therapy must be continued for at least 3 weeks or until all lesions have completely epithelialized.

Q: Which of the following is least likely to be a mode of transmission of Hansen's disease?

Transplacental. **Explanation:** Hansen’s disease (Leprosy), caused by *Mycobacterium leprae*, primarily spreads through prolonged, close contact with untreated multibacillary patients. **1. Why Transplacental is the Correct Answer:** While *M. leprae* has been detected in the placenta and umbilical cord blood of infected mothers, **congenital transmission (transplacental) is extremely rare and considered the least likely mode of transmission.** Most children born to mothers with leprosy are born healthy. The risk to the infant primarily arises from post-natal exposure to the mother’s respiratory droplets or skin contact rather than intrauterine infection. **2. Analysis of Other Options:** * **Droplet Infection (Option B):** This is the **most common and primary route** of transmission. Large numbers of bacilli are shed from the nasal mucosa of untreated lepromatous patients during sneezing or coughing. * **Breast Milk (Option D):** *M. leprae* has been demonstrated in the breast milk of lactating mothers with lepromatous leprosy. While not the primary route, it is a documented potential vehicle for transmission. * **Mosquito Bite (Option A):** Arthropod vectors (mosquitos, bedbugs, and flies) have been shown to carry *M. leprae* mechanically. While their epidemiological significance is debated, they are recognized as a possible minor mode of transmission in endemic areas. **Clinical Pearls for NEET-PG:** * **Incubation Period:** Longest among bacterial infections (Average: 3–5 years). * **Primary Site of Entry:** Respiratory tract (nasal mucosa) is the most accepted portal of entry. * **Armadillos:** Known natural non-human reservoirs of *M. leprae*. * **Cooler Temperatures:** The organism prefers temperatures of 27–30°C, explaining its predilection for peripheral nerves, skin, and the anterior chamber of the eye.

Tropical Dermatology Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following conditions is characterized by the sign of the groove?

A. Lymphogranuloma venereum (Correct Answer)
B. Granuloma inguinale
C. Syphilis
D. Chancroid

Explanation: **Explanation:** **Lymphogranuloma venereum (LGV)** is caused by the **L1, L2, and L3 serovars of *Chlamydia trachomatis***. The "Sign of the Groove" (Greenblatt’s sign) is a pathognomonic clinical finding in the secondary stage of LGV. It occurs when the inguinal and femoral lymph nodes enlarge simultaneously, separated by the rigid **inguinal ligament**. This creates a visible depression or "groove" between the two groups of inflamed lymph nodes. **Analysis of Incorrect Options:** * **B. Granuloma Inguinale (Donovanosis):** Caused by *Klebsiella granulomatis*. It presents with painless, beefy-red, velvety ulcers. It is characterized by "pseudobuboes" (subcutaneous granulation tissue) rather than true lymphadenopathy. * **C. Syphilis:** Primary syphilis presents with a painless, indurated "hard chancre." While it causes bilateral inguinal lymphadenopathy, the nodes are discrete, rubbery, and do not form a groove. * **D. Chancroid:** Caused by *Haemophilus ducreyi*. It presents with painful, soft ulcers and painful inflammatory buboes that are usually unilateral and may suppurate, but they do not form the characteristic groove sign. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of LGV:** Primary (painless papule/ulcer), Secondary (Inguinal syndrome with the Groove sign), and Tertiary (Genito-anorectal syndrome/Elephantiasis). * **Diagnosis:** Frei test (historical), NAAT (current gold standard), and **Donovan bodies** (safety-pin appearance) are seen in Donovanosis, NOT LGV. * **Treatment:** Doxycycline (100 mg BID for 21 days) is the drug of choice for LGV.

Question 2: A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?

A. Sweet's Syndrome
B. Erythema nodosum (Correct Answer)
C. Erythema nodosum leprosum
D. Behcet's syndrome

Explanation: ### Explanation **Correct Answer: B. Erythema nodosum** **Why it is correct:** Erythema nodosum (EN) is the most common form of **septal panniculitis**. Clinically, it presents as tender, erythematous nodules typically located over the **pretibial area (shins)**, often accompanied by fever and malaise. Histopathologically, early lesions show edema and neutrophilic infiltration of the septa. As the lesion evolves, it is characterized by **Miescher’s radial granulomas**—small clusters of spindle-shaped or **foamy histiocytes** surrounding a central cleft. The absence of vasculitis is a hallmark feature that distinguishes EN from other forms of panniculitis. **Why the other options are incorrect:** * **A. Sweet’s Syndrome:** This is a neutrophilic dermatosis characterized by "juicy" erythematous plaques and high fever. Histology shows dense dermal neutrophilic infiltrate with papillary dermal edema, but it is not a primary panniculitis and does not typically present with foamy histiocytes in the septa. * **C. Erythema nodosum leprosum (ENL):** While ENL also presents with tender nodules and fever, it is a Type 2 Lepra reaction. Histologically, it is a **lobular panniculitis** and, crucially, it **must show evidence of vasculitis** (leukocytoclastic vasculitis) and the presence of *M. leprae* (AFB positive). * **D. Behcet’s syndrome:** While it can cause EN-like lesions, the systemic involvement (oral/genital ulcers, uveitis) and the characteristic histopathology (often showing vasculitis) do not fit the isolated description provided. **NEET-PG High-Yield Pearls:** * **Most common cause of EN:** Idiopathic (followed by Streptococcal infections, Sarcoidosis, and TB). * **Histopathology Key:** Septal panniculitis **without** vasculitis = Erythema Nodosum. * **Löfgren Syndrome:** Triad of EN, bilateral hilar lymphadenopathy, and arthritis (highly suggestive of Sarcoidosis). * **Miescher’s Radial Granulomas:** Pathognomonic histological finding for EN.

Question 3: A young tourist presents with an erythematous lesion on the cheek with central crusting after visiting a region endemic for a specific protozoal infection. What is the likely dermatological condition?

A. Cutaneous Leishmaniasis (Correct Answer)
B. Systemic Lupus Erythematosus
C. Lupus vulgaris
D. Chilblains

Explanation: ### Explanation **Correct Option: A. Cutaneous Leishmaniasis** Cutaneous Leishmaniasis (CL), often referred to as "Oriental Sore" or "Delhi Boil," is caused by the protozoan *Leishmania* species and transmitted by the bite of an infected **female sandfly (*Phlebotomus*)**. The classic presentation begins as a small erythematous papule at the inoculation site (usually exposed areas like the face), which evolves into a nodule and eventually develops **central crusting** or ulceration with a raised, indurated border. The history of travel to an endemic region is a crucial diagnostic clue. **Why Incorrect Options are Wrong:** * **B. Systemic Lupus Erythematosus (SLE):** Typically presents with a "malar rash" (butterfly distribution) that spares the nasolabial folds. It is an autoimmune condition, not associated with travel to protozoal endemic areas or central crusting. * **C. Lupus Vulgaris:** This is a chronic form of cutaneous tuberculosis. While it affects the face, it typically presents as "apple-jelly" nodules on diascopy and follows a very chronic, progressive course rather than an acute post-travel presentation. * **D. Chilblains (Pernio):** An inflammatory response to cold, damp conditions. It presents as itchy, purple-red bumps on fingers or toes, not as a crusted facial lesion following tropical travel. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** Female Sandfly (*Phlebotomus*). * **Diagnosis:** Skin biopsy or slit-skin smear showing **LD bodies** (Leishman-Donovan bodies) within macrophages. * **Treatment of Choice:** Intralesional or systemic **Sodium Stibogluconate** (Pentavalent antimonials) or Miltefosine. * **Volcano Sign:** The appearance of a crusted ulcer with a central pit is often described as the "volcano sign."

Question 4: A child from Bihar presents with hypopigmented patches on the face. What is the most likely diagnosis?

A. Pityriasis alba
B. Leprosy (Correct Answer)
C. Vitiligo
D. None of the above

Explanation: **Explanation:** In the context of NEET-PG, the geographical location provided in a clinical stem is a critical diagnostic clue. **Bihar** is a highly endemic region for **Leprosy (Hansen’s Disease)** in India. In an endemic area, any hypopigmented patch in a child should be considered Leprosy until proven otherwise. The diagnosis is clinically supported by the presence of sensory loss (anesthesia/hypoesthesia) within the patch and/or thickened peripheral nerves. **Analysis of Options:** * **Leprosy (Correct):** The most common presentation in children is a solitary, ill-defined hypopigmented patch (Tuberculoid or Indeterminate spectrum). The epidemiological link to Bihar makes this the most likely diagnosis for exam purposes. * **Pityriasis alba:** This also presents as hypopigmented patches on the face of children, often associated with atopy. However, the patches usually have fine scaling and lack the sensory loss or nerve involvement characteristic of Leprosy. * **Vitiligo:** This presents as "depigmented" (chalky white) macules rather than "hypopigmented" patches. The borders are usually well-defined, and sensation remains intact. **Clinical Pearls for NEET-PG:** * **Cardinal Signs of Leprosy:** 1. Hypopigmented/erythematous patches with definite loss of sensation. 2. Thickened/tender peripheral nerves. 3. Positive skin smear for Acid Fast Bacilli (*M. leprae*). * **Differential Diagnosis:** For a hypopigmented patch on the face, always consider *Pityriasis versicolor* (fungal, "spaghetti and meatballs" appearance on KOH) and *Post-inflammatory hypopigmentation*. * **High-Yield Fact:** The most common nerve involved in Leprosy is the **Ulnar nerve**, but the most common nerve involved in the face is the **Zygomatic branch of the Facial nerve** (leading to lagophthalmos).

Question 5: What is the early reaction of the Lepromin test known as?

A. Late Mitsuda reaction
B. Fernandez reaction (Correct Answer)
C. Early Mitsuda reaction
D. First lepromin reaction

Explanation: The **Lepromin test** is a skin test used to measure the cell-mediated immunity (CMI) of a patient against *Mycobacterium leprae*. It is not a diagnostic test for leprosy but is used for classification and prognosis. ### Explanation of the Correct Answer The **Fernandez reaction** is the **early reaction** observed in the Lepromin test. It occurs **48 to 72 hours** after the intradermal injection of lepromin. It is a Type IV (delayed-type) hypersensitivity reaction to the soluble bacterial proteins. A positive Fernandez reaction indicates that the individual has been previously sensitized to *M. leprae* antigens. ### Why Other Options are Incorrect * **Late Mitsuda reaction (Option A):** This is the **late reaction** observed **3 to 4 weeks** after the injection. It represents a granulomatous response to the bacillary components of the lepromin. It is highly positive in Tuberculoid leprosy (TT) and negative in Lepromatous leprosy (LL). * **Early Mitsuda reaction (Option C):** This is a misnomer. The Mitsuda reaction is inherently a late-phase reaction. * **First lepromin reaction (Option D):** This is not a standard medical term used to describe the phases of the Lepromin test. ### High-Yield Clinical Pearls for NEET-PG * **Prognostic Value:** A positive Mitsuda reaction indicates strong CMI and a better prognosis (Tuberculoid end of the spectrum). * **Classification:** Lepromin test is **Negative** in Lepromatous Leprosy (LL) due to anergy and **Positive** in Tuberculoid Leprosy (TT). * **Antigen Types:** * *Lepromin H (Hayashi):* Derived from human leproma. * *Lepromin A (Armadillo):* Derived from armadillo-grown bacilli (more commonly used today). * **Memory Aid:** **F**ernandez = **F**ast (48-72 hours); **M**itsuda = **M**onth (approx. 3-4 weeks).

Question 6: Which of the following are clinical features of Erythema nodosum leprosum?

A. Fever (Correct Answer)
B. Hepatitis
C. Joint pain
D. Skin eruptions

Explanation: **Erythema Nodosum Leprosum (ENL)**, also known as a **Type 2 Lepra Reaction**, is a systemic immune-complex mediated (Type III hypersensitivity) reaction occurring primarily in lepromatous (LL) and borderline lepromatous (BL) leprosy. ### **Explanation of Options** * **A. Fever (Correct):** ENL is a multi-systemic inflammatory syndrome. **Fever** is the most common and characteristic constitutional symptom, often accompanied by malaise and prostration. It signifies the acute systemic nature of the immune response against released *M. leprae* antigens. * **B. Hepatitis:** While ENL can cause multi-organ involvement (like nephritis or orchitis), clinically significant hepatitis is not a standard or defining feature of the reaction. * **C. Joint Pain:** Although arthralgia can occur in ENL, "Fever" is considered the hallmark systemic sign in standard medical examinations. In many MCQ formats, if forced to choose the most definitive systemic feature, fever takes precedence. * **D. Skin Eruptions:** While ENL presents with painful, evanescent subcutaneous nodules, the term "skin eruptions" is too non-specific. The question specifically tests the recognition of the **systemic** inflammatory markers of the reaction. ### **Clinical Pearls for NEET-PG** * **Mechanism:** Type III Hypersensitivity (Immune-complex deposition). * **Classic Presentation:** Tender, erythematous, evanescent (short-lived) nodules appearing in crops, usually on the pretibial surface and face. * **Associated Features:** Neuritis, dactylitis, iridocyclitis, orchitis, and lymphadenopathy. * **Drug of Choice:** **Thalidomide** is the most effective treatment for ENL. Prednisolone and Clofazimine are also used. * **Trigger:** Often precipitated by starting Multi-Drug Therapy (MDT), pregnancy, or stress.

Question 7: An 8-year-old boy presents with a white, non-anesthetic, non-scaly hypopigmented macule on his face. What is the likely diagnosis?

A. Pityriasis alba
B. Pityriasis versicolor
C. Indeterminate leprosy (Correct Answer)
D. Neuritic leprosy

Explanation: ### Explanation The correct diagnosis is **Indeterminate Leprosy**. This is the earliest clinical stage of leprosy, often seen in children. It typically presents as a single, poorly defined, hypopigmented macule, most commonly on the face, extensor surfaces, or buttocks. **Why Indeterminate Leprosy is correct:** In the early stages of leprosy, nerve damage is not yet extensive. Therefore, the classic signs of leprosy—such as **anesthesia** (loss of sensation) and **anhidrosis** (loss of sweating)—are frequently **absent**. The presence of a non-anesthetic, non-scaly hypopigmented macule in an endemic area should always raise suspicion for indeterminate leprosy. **Why the other options are incorrect:** * **Pityriasis alba:** While it also presents as hypopigmented macules on the face of children, it is characterized by **fine, powdery scaling** and is often associated with atopic dermatitis. * **Pityriasis versicolor:** This fungal infection presents with **fine scaling** (demonstrated by the "coup d'ongle" or scratch sign) and typically affects the trunk rather than the face in children. * **Neuritic leprosy:** This form involves nerve trunks without any visible skin lesions. It presents with motor weakness, sensory loss, or nerve thickening, but not with a hypopigmented macule. **NEET-PG High-Yield Pearls:** * **Indeterminate Leprosy:** Most cases (approx. 75%) self-heal; others evolve into the polar forms (TT or LL) depending on the patient's cell-mediated immunity. * **Histopathology:** Shows a non-specific perivascular and periappendageal lymphocytic infiltrate. Acid-fast bacilli (AFB) are rarely found. * **Clinical Tip:** If a hypopigmented patch on a child's face is **non-scaly** and **non-itchy**, think Indeterminate Leprosy first in the Indian context.

Question 8: Which of the following is true for multibacillary leprosy?

A. More than 5 lesions on skin smears
B. Clofazimine is an important drug to be given
C. Treatment is to be given for 12 months
D. All of the above (Correct Answer)

Explanation: **Explanation:** Leprosy (Hansen’s Disease) is classified by the WHO into **Paucibacillary (PB)** and **Multibacillary (MB)** types based on clinical and bacteriological criteria to simplify field treatment. 1. **Option A (Lesion Count):** According to the WHO classification, patients with **more than 5 skin lesions** are categorized as Multibacillary. Additionally, if a skin smear is positive at any site (regardless of the number of lesions), the case is classified as MB. 2. **Option B (Clofazimine):** The standard WHO Multi-Drug Therapy (MDT) for MB leprosy consists of three drugs: **Rifampicin, Dapsone, and Clofazimine**. Clofazimine is crucial as it provides both bactericidal action and anti-inflammatory properties, which help in preventing Type 2 Lepra reactions (ENL). 3. **Option C (Duration):** The recommended duration for MB-MDT is **12 months** (12 blister packs to be completed within 18 months). In contrast, PB leprosy is treated for 6 months. Since all three statements accurately describe the management and classification of Multibacillary leprosy, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **MDT Regimen (MB):** Rifampicin (600mg once monthly), Clofazimine (300mg once monthly + 50mg daily), and Dapsone (100mg daily). * **Cardinal Signs:** Hypopigmented/reddish patches with loss of sensation, thickened peripheral nerves, and positive skin smears. * **Drug Side Effects:** Clofazimine causes brownish-black skin discoloration; Dapsone can cause hemolysis or "Dapsone Syndrome." * **Accompanied PB Criteria:** 1–5 lesions and no nerve/single nerve involvement.

Question 9: What is the drug of choice for Granuloma venereum?

A. Sulfonamides
B. Streptomycin
C. Penicillin
D. Erythromycin (Correct Answer)

Explanation: **Explanation:** **Granuloma venereum**, also known as **Donovanosis**, is a chronic, progressive bacterial infection of the genital and perianal regions caused by the Gram-negative intracellular organism *Klebsiella granulomatis* (formerly *Calymmatobacterium granulomatis*). **Why Erythromycin is the Correct Answer:** According to standard dermatological guidelines and traditional textbooks (like IADVL), **Erythromycin** (500 mg four times daily) is considered a primary drug of choice, particularly in pregnancy. However, it is important to note that modern CDC guidelines now recommend **Azithromycin** (1g weekly or 500mg daily) as the first-line treatment due to better compliance. In the context of this specific MCQ, Erythromycin remains the most appropriate choice among the provided options. **Why Other Options are Incorrect:** * **Sulfonamides:** These were used historically but are no longer preferred due to high rates of bacterial resistance and lower efficacy compared to macrolides. * **Streptomycin:** While effective, it requires intramuscular administration and carries risks of ototoxicity and nephrotoxicity, making it a second or third-line alternative. * **Penicillin:** *Klebsiella granulomatis* is inherently resistant to Penicillin; it is the drug of choice for Syphilis, not Donovanosis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Donovan Bodies:** Pathognomonic finding; these are safety-pin shaped organisms seen within large vacuolated macrophages on a **crush smear** (Giemsa or Wright stain). 2. **Clinical Presentation:** Characterized by **painless, beefy-red, velvety ulcers** that bleed easily on touch (friable). 3. **Pseudobubo:** It does not cause true lymphadenopathy; instead, it causes "pseudobuboes," which are subcutaneous granulomatous swellings in the inguinal region. 4. **Treatment Duration:** Therapy must be continued for at least 3 weeks or until all lesions have completely epithelialized.

Question 10: Which of the following is least likely to be a mode of transmission of Hansen's disease?

A. Mosquito bite
B. Droplet infection
C. Transplacental (Correct Answer)
D. Breast milk

Explanation: **Explanation:** Hansen’s disease (Leprosy), caused by *Mycobacterium leprae*, primarily spreads through prolonged, close contact with untreated multibacillary patients. **1. Why Transplacental is the Correct Answer:** While *M. leprae* has been detected in the placenta and umbilical cord blood of infected mothers, **congenital transmission (transplacental) is extremely rare and considered the least likely mode of transmission.** Most children born to mothers with leprosy are born healthy. The risk to the infant primarily arises from post-natal exposure to the mother’s respiratory droplets or skin contact rather than intrauterine infection. **2. Analysis of Other Options:** * **Droplet Infection (Option B):** This is the **most common and primary route** of transmission. Large numbers of bacilli are shed from the nasal mucosa of untreated lepromatous patients during sneezing or coughing. * **Breast Milk (Option D):** *M. leprae* has been demonstrated in the breast milk of lactating mothers with lepromatous leprosy. While not the primary route, it is a documented potential vehicle for transmission. * **Mosquito Bite (Option A):** Arthropod vectors (mosquitos, bedbugs, and flies) have been shown to carry *M. leprae* mechanically. While their epidemiological significance is debated, they are recognized as a possible minor mode of transmission in endemic areas. **Clinical Pearls for NEET-PG:** * **Incubation Period:** Longest among bacterial infections (Average: 3–5 years). * **Primary Site of Entry:** Respiratory tract (nasal mucosa) is the most accepted portal of entry. * **Armadillos:** Known natural non-human reservoirs of *M. leprae*. * **Cooler Temperatures:** The organism prefers temperatures of 27–30°C, explaining its predilection for peripheral nerves, skin, and the anterior chamber of the eye.

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Cutaneous Leishmaniasis

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Leprosy

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Cutaneous Larva Migrans

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Myiasis

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Cutaneous Manifestations of Malaria

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Dengue and Other Viral Hemorrhagic Fevers

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Global Health Perspectives in Dermatology

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