Bacterial Skin Infections Practice Questions

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: A 7-year-old child presents with a hypo-pigmented anesthetic patch on the face. What is the most probable diagnosis?

Intermediate leprosy. ### Explanation The diagnosis of **Indeterminate Leprosy** is based on the classic clinical triad of leprosy: a hypopigmented patch, loss of sensation, and (potentially) nerve involvement. **1. Why Indeterminate Leprosy is Correct:** In the context of pediatric dermatology and the NEET-PG exam, a **hypopigmented patch with anesthesia** (loss of sensation) is pathognomonic for leprosy. Indeterminate leprosy is the earliest clinical stage, often seen in children. It typically presents as a single, ill-defined, hypopigmented macule. While sensation may be only slightly diminished in early stages, the presence of anesthesia definitively points toward a mycobacterial infection affecting the dermal nerves. **2. Why Other Options are Incorrect:** * **Pityriasis alba:** Common in children; presents as multiple, ill-defined, scaly hypopigmented patches on the face. Crucially, **sensation is intact**, and it is often associated with atopy. * **Nevus anemicus:** A congenital vascular anomaly where the area appears pale due to localized hypersensitivity to catecholamines (vasoconstriction). Sensation is normal, and the patch **disappears on diascopy** (pressure with a glass slide) or rubbing. * **Nevus achromicus (Nevus Depigmentosus):** A stable, congenital hypopigmented birthmark. It has **normal sensation** and does not change in size or pigment over time. **Clinical Pearls for NEET-PG:** * **Earliest sign of Leprosy:** Usually a solitary hypopigmented macule (Indeterminate). * **First sensation lost:** Temperature (Cold/Hot), followed by Touch, Pain, and Deep Pressure. * **Face involvement:** In children, the face is a common site for leprosy due to increased exposure to the environment/vectors. * **Histopathology:** Indeterminate leprosy shows non-specific lymphocytic infiltration around dermal appendages and nerves; Acid-Fast Bacilli (AFB) are rarely found.

Q: Lucio reaction is seen in which of the following conditions?

Leprosy. **Explanation:** **Lucio reaction** (also known as *phenomenon of Lucio*) is a rare, severe, and life-threatening type of reactional state specifically seen in patients with **Diffuse Lepromatous Leprosy (DLL)**. It is most commonly associated with the non-nodular, "pure and primitive" diffuse form of leprosy (Lucio-Latapi leprosy), particularly in patients from Mexico and Central America. **Why Leprosy is correct:** The underlying mechanism is a **necrotizing vasculitis** caused by direct invasion of the endothelial cells of blood vessels by *Mycobacterium leprae*. This leads to vascular occlusion, tissue infarction, and subsequent large, jagged, "punched-out" necrotic ulcers. Unlike Type 2 Lepra reactions (Erythema Nodosum Leprosum), Lucio reaction does not typically present with systemic fever or constitutional symptoms initially, but focuses on cutaneous infarcts. **Why other options are incorrect:** * **Tuberculosis:** While TB can cause various skin manifestations (like Lupus Vulgaris or Scrofuloderma), it does not manifest as Lucio reaction. * **Syphilis:** Secondary syphilis presents with a generalized maculopapular rash (including palms and soles) or Condyloma lata, but not necrotizing vasculitis of this type. * **Lymphogranuloma venereum (LGV):** Caused by *Chlamydia trachomatis*, it primarily affects the lymphatics (buboes) and anogenital area, not the systemic vascular system. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Standard WHO MDT for Leprosy; however, systemic corticosteroids and wound care are vital. Thalidomide is generally **not** effective for Lucio reaction (unlike ENL). * **Histopathology:** Shows massive infiltration of the dermis and blood vessel walls by Acid-Fast Bacilli (AFB). * **Triad of Lucio Leprosy:** Diffuse skin infiltration, alopecia of eyebrows/eyelashes, and the Lucio phenomenon.

Q: The primary lesion of syphilis, the Hunterian chancre, is characterized by which of the following features, EXCEPT?

Bleeding. The primary lesion of syphilis, the **Hunterian chancre**, is the hallmark of primary syphilis, appearing approximately 3 weeks after inoculation with *Treponema pallidum*. [1] ### **Why "Bleeding" is the Correct Answer** A classic syphilitic chancre is characterized by its **clean base**. Unlike many other genital ulcers, it does **not bleed easily** on manipulation. If the surface is scraped, it typically exudes a clear, serous fluid rich in treponemes (visible on dark-field microscopy) rather than blood. ### **Explanation of Other Options** * **Painless (Option A):** This is a defining feature. The chancre is characteristically non-tender unless secondary bacterial infection occurs. [1] * **Indurated (Option B):** The term "Hunterian" refers to the button-like, firm, or cartilaginous consistency (induration) of the ulcer's base and margins. * **Shallow Ulcer (Option C):** The lesion typically begins as a papule that erodes into a shallow, well-demarcated ulcer with a "punched-out" appearance. ### **High-Yield Clinical Pearls for NEET-PG** * **Lymphadenopathy:** Primary syphilis is associated with **painless, non-suppurative, rubbery** regional lymphadenopathy (usually bilateral inguinal). [1] * **Diagnosis:** The gold standard for primary syphilis is **Dark-field microscopy**. Serological tests (VDRL/RPR) may be negative in the first 1–2 weeks of the chancre's appearance. * **Differential Diagnosis:** * **Chancroid (Haemophilus ducreyi):** Painful, soft, and **bleeds easily** (the opposite of syphilis). * **Herpes Simplex:** Multiple, painful, superficial vesicles/ulcers. * **Treatment:** The drug of choice is **Benzathine Penicillin G** (2.4 million units IM, single dose).

Q: A 12-year-old boy presents with a white facial lesion that has grown noticeably large. Examination reveals hypoesthesia over the lesion and a smooth surface. What is the likely diagnosis?

Indeterminate leprosy. **Explanation:** The clinical presentation of a **hypopigmented (white) lesion** with **hypoesthesia** (loss of sensation) in a young patient is a classic hallmark of **Indeterminate Leprosy**. 1. **Why Indeterminate Leprosy is correct:** This is the earliest clinical stage of leprosy. It typically presents as a single, ill-defined, hypopigmented macule. The crucial diagnostic feature is the **impairment of sensation** (temperature or touch) and/or decreased sweating within the patch, caused by early nerve involvement. In children, the face is a common site. Histopathology usually shows a non-specific lymphocytic infiltration around nerves and appendages. 2. **Why other options are incorrect:** * **Lepromatous Leprosy (LL):** This is the multibacillary, polar end of the spectrum. It presents with multiple, symmetrical, shiny nodules or plaques and widespread infiltration (Leonine facies). Sensation is usually preserved in early LL lesions. * **Pityriasis Alba:** A common pediatric condition (often associated with atopy) presenting as ill-defined hypopigmented patches with fine scaling. Crucially, there is **no sensory loss**. * **Asbestosis:** This is a restrictive lung disease caused by asbestos fiber inhalation; it has no relevance to hypopigmented skin lesions. **NEET-PG High-Yield Pearls:** * **Cardinal Signs of Leprosy (WHO):** 1. Hypopigmented/reddish patch with definite loss of sensation. 2. Thickened peripheral nerves. 3. Positive skin smear for Acid Fast Bacilli. * **Indeterminate Leprosy** often heals spontaneously or evolves into other types (Tuberculoid or Lepromatous) depending on the host's cell-mediated immunity (CMI). * **Differential for Hypopigmented patches:** If sensation is lost, think Leprosy. If sensation is intact, consider Pityriasis alba, Vitiligo, or Tinea versicolor.

Q: Cutaneous tuberculosis secondary to underlying infected tissue, such as lymph nodes, is called as?

Scrofuloderma. **Explanation:** **Scrofuloderma (Tuberculosis Colliquativa Cutis)** is the correct answer. It represents a **pericontiguous spread** of tuberculosis to the overlying skin from an underlying infected focus, most commonly a **tuberculous lymph node** (especially cervical), but also from infected bones or joints. It typically presents as firm, painless subcutaneous nodules that eventually break down to form ulcers and sinus tracts with a characteristic "watery" or "cheesy" discharge. **Analysis of Incorrect Options:** * **Lupus Vulgaris:** This is the most common chronic form of cutaneous TB in adults. It occurs via hematogenous, lymphatic, or contiguous spread in individuals with high immunity. The hallmark clinical sign is the **"Apple-jelly nodule"** seen on diascopy. * **Spina Ventosa:** This refers to **tuberculous dactylitis**, involving the short bones of the hands or feet. While it can lead to scrofuloderma of the overlying skin, the term itself refers to the bone pathology, not the cutaneous manifestation. * **Tuberculous Verrucosa Cutis (TVC):** Also known as "Prosector’s wart," this is a form of **exogenous inoculation** TB occurring in previously sensitized individuals with high immunity. It presents as a solitary, warty (verrucous) plaque, usually on the hands. **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** Cutaneous TB is classified based on the bacterial load (**Multibacillary** vs. **Paucibacillary**) and the route of infection. * **Paucibacillary forms:** Lupus Vulgaris, TVC, and Tuberculids. * **Multibacillary forms:** Scrofuloderma, Orificial TB, and Miliary TB. * **Most common type in India:** Lupus Vulgaris (overall), though Scrofuloderma is very common in children.

Q: Which of the following diseases is associated with Erythema migrans?

Lyme's disease. **Explanation:** **Lyme’s Disease (Correct Answer):** Erythema migrans (EM) is the pathognomonic clinical sign of early localized Lyme disease, caused by the spirochete *Borrelia burgdorferi* and transmitted by the *Ixodes* tick. It typically appears 3 to 30 days after a tick bite as an expanding red patch that often clears centrally, creating a classic **"bull’s-eye"** or targetoid appearance. **Analysis of Incorrect Options:** * **Endemic Typhus:** Caused by *Rickettsia typhi* (transmitted by rat fleas). It typically presents with a maculopapular rash starting on the trunk and spreading peripherally, but does not feature erythema migrans. * **Scrub Typhus:** Caused by *Orientia tsutsugamushi*. Its hallmark cutaneous finding is an **eschar** (a necrotic sore with a black crust) at the site of the chigger bite, accompanied by lymphadenopathy. * **Master’s Disease:** Also known as Southern Tick-Associated Rash Illness (STARI). While it produces a rash nearly identical to erythema migrans, it is associated with the *Amblyomma americanum* (Lone Star tick) and is etiologically distinct from Lyme disease. In the context of standard medical examinations, EM is most classically linked to Lyme disease. **NEET-PG High-Yield Pearls:** * **Vector:** *Ixodes* tick (also transmits Babesiosis and Anaplasmosis). * **Stages of Lyme:** 1. Early Localized (Erythema migrans). 2. Early Disseminated (Multiple EM lesions, Bell’s palsy, AV block). 3. Late (Chronic arthritis, Acrodermatitis chronica atrophicans). * **Treatment of Choice:** Doxycycline (Amoxicillin in children <8 years or pregnant women). * **Important Distinction:** Do not confuse the "target lesions" of Erythema Multiforme (associated with HSV) with the "bull's-eye" of Erythema Migrans.

Q: Which of the following is NOT a characteristic of secondary syphilis?

Painful and itchy maculopapular lesions. Syphilis, caused by the spirochete *Treponema pallidum*, is a multi-stage systemic infection. Understanding the clinical presentation of each stage is crucial for NEET-PG. **Why Option B is the Correct Answer:** The hallmark of secondary syphilis is a generalized **non-pruritic (not itchy)** and **painless** maculopapular rash [1]. The rash characteristically involves the **palms and soles**, a high-yield clinical sign [1]. Because the question asks for the "NOT" characteristic, Option B is correct because syphilitic lesions are typically asymptomatic [1]. **Analysis of Incorrect Options:** * **Option A:** Secondary syphilis typically manifests **6 to 8 weeks** (range 2–12 weeks) after the appearance of the primary chancre. In some cases, the chancre may still be healing when the secondary stage begins. * **Option C:** Unlike the primary stage, secondary syphilis is a systemic illness. Patients frequently present with **constitutional symptoms** such as malaise, fever, sore throat, weight loss, and generalized lymphadenopathy (especially epitrochlear nodes). * **Option D:** This stage represents hematogenous dissemination. While rare, it can lead to **organ-specific complications** including aseptic meningitis, hepatitis (with disproportionately high alkaline phosphatase), immune-complex glomerulonephritis (nephrotic syndrome), and ocular involvement like uveitis. **Clinical Pearls for NEET-PG:** * **Condyloma Lata:** Highly infectious, moist, wart-like papules found in intertriginous areas (e.g., axilla, perineum) during the secondary stage [1]. * **Lues Maligna:** A severe, pleomorphic form of secondary syphilis with necrotic lesions, usually seen in HIV-positive patients. * **Diagnosis:** Non-specific treponemal tests (VDRL/RPR) have their highest titers during the secondary stage. If the titer is extremely high, a "Prozone phenomenon" may cause a false negative.

Q: Hutchinson's triad is seen in which of the following conditions?

Congenital syphilis. **Explanation:** **Hutchinson’s Triad** is a classic clinical diagnostic marker for **Late Congenital Syphilis** (presenting after 2 years of age). It occurs due to the systemic inflammatory response to *Treponema pallidum* during fetal development and early childhood. The triad consists of: 1. **Hutchinson’s Teeth:** Notched, peg-shaped permanent upper central incisors. 2. **Interstitial Keratitis:** Chronic inflammation of the corneal stroma leading to corneal scarring and potential blindness (usually appears between ages 5–15). 3. **Sensorineural Hearing Loss:** Caused by eighth cranial nerve (vestibulocochlear) involvement. **Analysis of Options:** * **Option B (Correct):** Congenital syphilis is the only condition where this developmental triad occurs. It is divided into Early (birth to 2 years) and Late (>2 years) stages. * **Option A, C, & D (Incorrect):** Acquired syphilis (Primary, Secondary, and Tertiary) occurs after birth via sexual contact or inoculation. While these stages can involve the eyes (uveitis) or ears (otosyphilis), they do not cause the specific developmental dental deformities or the classic triad seen in the congenital form. **High-Yield Clinical Pearls for NEET-PG:** * **Mulberry Molars:** Another dental sign of congenital syphilis characterized by multiple rudimentary cusps on the first permanent molars. * **Other Late Signs:** Saddle nose deformity, Sabre shins (anterior bowing of the tibia), and Clutton’s joints (painless symmetrical knee swelling). * **Early Signs:** Snuffles (syphilitic rhinitis), pemphigus syphiliticus (bullous lesions), and hepatosplenomegaly. * **Screening:** VDRL/RPR are used for screening; FTA-ABS is the confirmatory treponemal test.

Question 1

All of the following are true regarding the treatment of Syphilis, except:

Accepted Answer

Late latent syphilis is treated with 2.4 million units of Benzathine penicillin administered once.

Answer

The only acceptable treatment for syphilis in pregnancy is penicillin.

Answer

Early latent syphilis is treated with 2.4 million units of Benzathine penicillin administered once.

Answer

Neurosyphilis is treated with Aqueous penicillin G 18-24 million units intravenously daily.

Question 2

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

Accepted Answer

Fever

Answer

Hepatitis

Answer

Joint pain

Answer

Skin eruptions

Question 3

A 7-year-old child presents with a hypo-pigmented anesthetic patch on the face. What is the most probable diagnosis?

Accepted Answer

Intermediate leprosy

Answer

Pityriasis alba

Answer

Nevus anemicus

Answer

Nevus achromicus

Question 4

Lucio reaction is seen in which of the following conditions?

Accepted Answer

Leprosy

Answer

Tuberculosis

Answer

Syphilis

Answer

Lymphogranuloma venereum

Question 5

The primary lesion of syphilis, the Hunterian chancre, is characterized by which of the following features, EXCEPT?

Accepted Answer

Bleeding

Answer

Painless

Answer

Indurated

Answer

Shallow ulcer

Question 6

A 12-year-old boy presents with a white facial lesion that has grown noticeably large. Examination reveals hypoesthesia over the lesion and a smooth surface. What is the likely diagnosis?

Accepted Answer

Indeterminate leprosy

Answer

Lepromatous leprosy

Answer

Pityriasis alba

Answer

Asbestosis

Question 7

Cutaneous tuberculosis secondary to underlying infected tissue, such as lymph nodes, is called as?

Accepted Answer

Scrofuloderma

Answer

Lupus Vulgaris

Answer

Spina Ventosa

Answer

Tuberculous Verrucosa Cutis

Question 8

Which of the following diseases is associated with Erythema migrans?

Accepted Answer

Lyme's disease

Answer

Endemic typhus

Answer

Scrub typhus

Answer

Master's disease

Question 9

Which of the following is NOT a characteristic of secondary syphilis?

Accepted Answer

Painful and itchy maculopapular lesions

Answer

Occurs 6-8 weeks after the development of the chancre

Answer

Constitutional features are present

Answer

Meningitis, hepatitis, glomerulonephritis, and uveitis may occur

Question 10

Hutchinson's triad is seen in which of the following conditions?

Accepted Answer

Congenital syphilis

Answer

Primary syphilis

Answer

Secondary syphilis

Answer

Tertiary syphilis

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

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