Tropical Dermatology

Tropical Dermatology Indian Medical PG Question 1: A forest officer develops the lesion as shown in the image. Which of the following is not a differential to consider?

• A. Cutaneous anthrax
• B. KFD (Correct Answer)
• C. Scrub typhus
• D. Healing brown recluse spider bite

Tropical Dermatology Explanation: ***KFD*** - **Kyasanur Forest Disease** (KFD) is a viral hemorrhagic fever, but it does **not** typically present with a **skin lesion** or eschar like the one shown. - KFD is characterized by fever, headache, myalgia, and gastrointestinal symptoms, with hemorrhagic manifestations in severe cases, but not a primary cutaneous lesion. *Cutaneous anthrax* - **Cutaneous anthrax** commonly presents as an **eschar**, often with surrounding edema and vesicles, which can resemble the lesion in the image. - Exposure through handling infected animal products or contact with contaminated soil is common, aligning with a forest officer's occupation. *Scrub typhus* - **Scrub typhus** characteristically causes an **eschar** (tache noire) at the bite site of the chigger mite. - The lesion in the image, an ulcer with a central black crust, is highly suggestive of such an eschar seen in rickettsial infections. *Healing brown recluse spider bite* - A **brown recluse spider bite** can cause a **necrotic ulcer** with a central dark eschar as the wound heals, fitting the appearance of the lesion. - The profession of a forest officer increases the likelihood of exposure to spiders in their natural habitat.

Tropical Dermatology Indian Medical PG Question 2: Kala azar is spread by –

• A. Black–fly
• B. Sand–fly (Correct Answer)
• C. Tsetse–fly
• D. House–fly

Tropical Dermatology Explanation: ***Sand–fly*** - Kala-azar, also known as **visceral leishmaniasis**, is transmitted to humans through the bite of an infected female **Phlebotomine sandfly**. - The sandfly acts as a **biological vector**, harboring the **Leishmania parasites** in its gut. *Black–fly* - **Black flies** are vectors for **onchocerciasis** (river blindness), caused by the parasite *Onchocerca volvulus*. - They are typically found near **fast-flowing water** and their bites often lead to skin nodules and eye lesions. *Tsetse–fly* - The **tsetse fly** is the vector for **African trypanosomiasis** (sleeping sickness), caused by species of *Trypanosoma*. - This disease primarily affects central nervous system function, leading to changes in sleep patterns. *House–fly* - **House flies** are primarily **mechanical vectors** for various pathogens, meaning they can transfer microbes from contaminated surfaces to food. - They are not known to transmit specific diseases like Kala-azar through a bite.

Tropical Dermatology Indian Medical PG Question 3: With reference to dengue virus, consider the following statements: 1. In India, all the four serotypes are found. 2. The reservoir of infection is both man and mosquito. 3. Adults usually have a milder disease than children. 4. Dengue hemorrhagic fever is caused by infection with more than one dengue virus. Which of the statements given above is/are correct?

• A. 2, 3 and 4
• B. 4 only
• C. 1, 2 and 4 (Correct Answer)
• D. 1 and 2 only

Tropical Dermatology Explanation: ***1, 2 and 4*** - **All four serotypes** (DEN-1, DEN-2, DEN-3, and DEN-4) of the dengue virus are endemic in India, contributing to the recurrent outbreaks seen across the country. - Dengue is a **vector-borne disease**, meaning the virus cycles between humans (the primary reservoir) and mosquitoes (specifically *Aedes aegypti* and *Aedes albopictus*), making both essential for its transmission. - **Dengue hemorrhagic fever (DHF)**, or severe dengue, is often associated with a **second infection by a different serotype** of the dengue virus due to antibody-dependent enhancement (ADE). *2, 3 and 4* - The statement that adults usually have a milder disease than children is **incorrect**; children often present with milder, non-specific symptoms, while adults are more likely to develop typical dengue fever or severe forms. - The other statements regarding the presence of all four serotypes, the reservoir, and the cause of DHF are correct. *4 only* - While statement 4 (DHF caused by infection with more than one serotype) is correct, it overlooks the accuracy of statements 1 and 2. - Omitting statements 1 and 2 makes this option incomplete as both are established facts about dengue. *1 and 2 only* - This option correctly identifies that all four serotypes exist in India and that humans and mosquitoes serve as reservoirs. - However, it **incorrectly excludes statement 4** regarding the etiology of dengue hemorrhagic fever (DHF), which results from sequential infection with a different serotype.

Tropical Dermatology Indian Medical PG Question 4: NVBDCP includes all except ?

• A. Filariasis
• B. Malaria
• C. Kala-azar
• D. Yellow fever (Correct Answer)

Tropical Dermatology Explanation: ***Yellow fever*** - Yellow fever is a **viral hemorrhagic fever** transmitted by infected mosquitoes, primarily **Aedes aegypti**. - While a significant public health concern, it is **not included in India's National Vector-Borne Disease Control Programme (NVBDCP)**, as it is not endemic to India. *Filariasis* - **Lymphatic filariasis** (elephantiasis) is a major vector-borne disease in India, caused by parasitic worms transmitted by mosquitoes. - It is a key component of the NVBDCP, which focuses on its elimination through **mass drug administration** and vector control. *Malaria* - **Malaria**, caused by Plasmodium parasites transmitted by Anopheles mosquitoes, is a cornerstone of the NVBDCP. - The program actively implements strategies for **case detection, treatment, vector control**, and preventing outbreaks. *Kala-azar* - **Kala-azar** (visceral leishmaniasis) is a severe parasitic disease transmitted by **sandflies**, making it a vector-borne disease. - It is one of the six diseases targeted by the NVBDCP for elimination, particularly in endemic regions of India.

Tropical Dermatology Indian Medical PG Question 5: A patient, a resident of Himachal Pradesh, presented with a series of ulcers in a row on his right leg. The biopsy from the affected area was taken and cultured on Sabouraud's dextrose agar. What is the most likely causative organism?

• A. Cladosporium spp.
• B. Pseudoallescheria boydii
• C. Nocardia brasiliensis
• D. Sporothrix schenckii (Correct Answer)

Tropical Dermatology Explanation: ***Sporothrix schenckii*** - The presentation of "ulcers in a row" on the leg is highly suggestive of **lymphocutaneous sporotrichosis**, a characteristic finding where the infection spreads via lymphatic drainage. - This fungus is endemic in certain regions including parts of **Himachal Pradesh**, and is typically acquired through contact with contaminated soil or plant material (e.g., rose thorns, sphagnum moss). - Grows well on **Sabouraud's dextrose agar**, producing characteristic colonies. *Cladosporium spp.* - While *Cladosporium* can cause **phaeohyphomycosis** or allergic fungal sinusitis, it does not typically present with the classic lymphocutaneous lesions described. - These fungi are common environmental contaminants and their infections are usually associated with chronic skin lesions, not a linear spread of ulcers. *Pseudoallescheria boydii* - *Pseudoallescheria boydii* is a common cause of **mycetoma** (Madura foot), characterized by chronic, destructive lesions with granulomas and sinus tracts that discharge grains. - This presentation is distinct from the linear ulcerative lesions described in the patient. *Nocardia brasiliensis* - *Nocardia brasiliensis* is a bacterium (an actinomycete) that causes **actinomycetoma**, characterized by chronic, suppurative lesions with sinus tracts discharging grains. - The characteristic **"ulcers in a row"** (lymphocutaneous spread pattern) is **not typical** of Nocardia infection, which presents as localized mycetoma rather than ascending lymphatic involvement. - While Nocardia can grow on some fungal media, the clinical presentation is the key distinguishing feature here.

Tropical Dermatology Indian Medical PG Question 6: Lupus vulgaris is:

• A. Squamous cell carcinoma
• B. Basal cell carcinoma
• C. Tuberculosis of skin (Correct Answer)
• D. Lupus erythematosus

Tropical Dermatology Explanation: ***Tuberculosis of skin*** - **Lupus vulgaris** is the most common form of **cutaneous tuberculosis** in developed countries, characterized by chronic, progressive skin lesions. - It results from **hematogenous** or **lymphatic spread** of *Mycobacterium tuberculosis* to the skin, often in individuals with good immunity. *Squamous cell carcinoma* - This is a type of **skin cancer** originating from the **keratinocytes**, usually presenting as a scaly, red patch or nodule. - While chronic skin lesions can sometimes predispose to SCC, lupus vulgaris itself is an infection, not a primary neoplastic process. *Basal cell carcinoma* - This is the most common form of **skin cancer**, typically appearing as a **pearly nodule** with telangiectasias, often on sun-exposed areas. - It is distinct from lupus vulgaris, which is an infectious disease of the skin with characteristic *apple-jelly* nodules on diascopy. *Lupus erythematosus* - This is a **systemic autoimmune disease** that can affect the skin in various ways, such as a **malar rash** or discoid lesions. - Although it shares the "lupus" name, it is fundamentally different from lupus vulgaris, which is a specific infectious condition caused by tuberculosis.

Tropical Dermatology Indian Medical PG Question 7: Which of the following statements regarding Paget's disease of nipple are correct? 1. It represents benign pathology of nipple areola complex 2. It is eczema like condition of nipple and areola 3. Erosion of nipple is seen 4. Nipple biopsy is required for definitive diagnosis Select the correct answer using the code given below:

• A. 2 and 4 only
• B. 1, 2 and 3
• C. 1, 3 and 4
• D. 2, 3 and 4 (Correct Answer)

Tropical Dermatology Explanation: ***2, 3 and 4*** - **Paget's disease** presents as an **eczema-like rash** on the nipple and areola, and is characterized by **nipple erosion** [1] and ulceration. - It is an **intraepithelial adenocarcinoma** of the nipple [1], and a definitive diagnosis requires a **nipple biopsy** [1] to identify Paget's cells [2]. *2 and 4 only* - This option is incomplete as it misses the important clinical feature of **nipple erosion**, which is a common presentation of Paget's disease. - While it correctly identifies the eczema-like appearance and the need for biopsy, it understates the full clinical picture. *1, 2 and 3* - Statement 1 is incorrect because Paget's disease of the nipple is a **malignant condition** [2], not a benign one. - It arises from **ductal carcinoma in situ** [1] or invasive breast cancer extending to the nipple epidermis. *1, 3 and 4* - Statement 1 is incorrect as **Paget's disease is malignant**, representing an underlying breast cancer [2], not a benign pathology. - This option incorrectly classifies the disease as benign, which is a critical misunderstanding of its nature. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1061-1062. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 456-457.

Tropical Dermatology Indian Medical PG Question 8: A lady from West Rajasthan presented with an ulcer surrounded by erythema on the right leg. Microscopy of the biopsy from the edge of the ulcer showed organisms with dark staining nuclei and kinetoplast. What is the most likely causative agent? (Refer to the provided image)

• A. Leishmania tropica (Correct Answer)
• B. Babesia microti
• C. Trypanosoma brucei
• D. Histoplasma capsulatum

Tropical Dermatology Explanation: ***Leishmania tropica*** - The presence of an ulcer with surrounding erythema in **West Rajasthan**, along with microscopy showing organisms with a **nucleus and kinetoplast**, is highly characteristic of **cutaneous leishmaniasis** caused by *Leishmania tropica*. - The organisms seen are **amastigotes** within macrophages in skin lesions, which are identified by their distinct **nucleus and kinetoplast** on microscopy. - West Rajasthan is an **endemic area** for cutaneous leishmaniasis. *Babesia microti* - *Babesia microti* causes **babesiosis**, a tick-borne illness affecting red blood cells, leading to **hemolytic anemia** and malaria-like symptoms. - It does not typically cause **skin ulcers** and its characteristic form in smears is a **ring form or tetrad ("Maltese cross")** within red blood cells, not organisms with kinetoplasts in macrophages. *Trypanosoma brucei* - *Trypanosoma brucei* causes **African trypanosomiasis (sleeping sickness)**, presenting with fever, headaches, joint pain, and neurological symptoms, possibly a **chancre** at the inoculation site. - While it has a **kinetoplast**, it exists as a flagellated **trypomastigote** in the blood and CSF, not as an **amastigote** in macrophages within a skin ulcer. - Additionally, this is **geographically incorrect** for West Rajasthan. *Histoplasma capsulatum* - *Histoplasma capsulatum* is a **fungus** that causes **histoplasmosis**, primarily affecting the respiratory system, especially in immunocompromised individuals. - It does **not possess a kinetoplast** and while it can cause disseminated disease with skin lesions, the microscopic appearance would be **yeast forms** within macrophages, not organisms with kinetoplasts.

Tropical Dermatology Indian Medical PG Question 9: Lines of Blaschko are related to?

• A. Keratinocytes (Correct Answer)
• B. Blood vessels
• C. Nerves
• D. Bones

Tropical Dermatology Explanation: ***Keratinocytes*** - **Lines of Blaschko** represent the migratory pathways of embryonic cells, primarily **keratinocytes**, in the skin. - These lines are not visible under normal conditions but become apparent in various **genetic skin disorders** where abnormal cells follow these specific patterns. *Blood vessels* - While blood vessels are extensively present in the skin, they do not follow the specific **migratory patterns** described by the Lines of Blaschko. - Their arrangement is more related to **vascular networks** and anatomical supply rather than embryonic cell migration. *Nerves* - **Nerves** in the skin have specific distributions, often following dermatomal patterns, which are distinct from the **Lines of Blaschko**. - Nerve distribution is related to their segmental origin from the **spinal cord**, not the migratory paths of epidermal cells. *Bones* - **Bones** are part of the skeletal system and are not found in the skin, making them unrelated to the **Lines of Blaschko**. - These lines describe epidermal cell migration, which is a feature of the **integumentary system**.

Tropical Dermatology Indian Medical PG Question 10: A 22-year-old woman presents with multiple tender, erythematous nodules on her shins that developed over the past week. She reports having a sore throat 2 weeks ago. She also complains of joint pain and fatigue. Physical examination reveals raised, red, tender nodules on the anterior surface of both legs. Her temperature is 38.2°C. Which of the following is the most likely diagnosis?

• A. Cellulitis
• B. Erythema nodosum (Correct Answer)
• C. Sweet syndrome
• D. Superficial thrombophlebitis

Tropical Dermatology Explanation: ***Erythema nodosum*** - The presentation of **tender, erythematous nodules on the shins**, following a preceding **sore throat**, with associated **joint pain and fatigue**, is highly characteristic of **erythema nodosum**. - It is a form of **panniculitis** typically triggered by infections (e.g., streptococcal pharyngitis), medications, or systemic diseases. *Cellulitis* - Characterized by a **warm, erythematous, swollen area** with poorly defined borders, often accompanied by pain and fever, but typically presents as a diffuse skin infection rather than distinct nodules. - While fever is present, the **nodular nature** of the lesions and their bilateral, symmetrical distribution are less consistent with cellulitis. *Sweet syndrome* - Also known as acute febrile neutrophilic dermatosis, it presents with **tender erythematous plaques or nodules** and **fever**, but typically has a more prominent **neutrophilic infiltrate** histologically. - Lesions of Sweet syndrome often appear on the **upper extremities, face, or neck**, and while it can affect the shins, the clinical picture here is more classic for erythema nodosum, especially given the history of sore throat. *Superficial thrombophlebitis* - Presents as a **palpable, tender, erythematous cord** along the course of a superficial vein, often with localized swelling and warmth. - The lesions are typically **linear or cord-like**, not discrete nodules scattered over the shins, and are directly related to a thrombosed vein.

Tropical Dermatology Flashcard 1 of 8

Question: Hyperpigmentation associated with _____ fever is macular and most commonly affects the nose and cheeks, also known as Chik sign

Answer: Chikungunya

Tropical Dermatology Flashcard 2 of 8

Question: Ill-defined hypopigmented patch over the face, along with a negative slit skin smear and normal sensations is suggestive of _____ leprosy

Answer: indeterminate

Tropical Dermatology Flashcard 3 of 8

Question: Tinea _____ is a type of tinea corporis that exists in the tropical climate

Answer: imbricata

Tropical Dermatology Flashcard 4 of 8

Question: Multibacillary leprosy involves _____ or more skin lesions with 2 or more nerves involves and SSS positive on any sites

Answer: 6

Tropical Dermatology Flashcard 5 of 8

Question: most characteristic skin lesion of leprosy is _____

Answer: hypopigmented and hypoaesthetic patch

Extra Information: 

Tropical Dermatology Flashcard 6 of 8

Question: In Lepromin test, late or Mitsuda test is positive at _____ days if there is onset of papule measuring =>5 mm

Answer: 21

Tropical Dermatology Flashcard 7 of 8

Question: In Lepromin test, early or Fernandez test is positive within _____ hours if there is the erythema measuring >10 mm

Answer: 48-72

Tropical Dermatology Flashcard 8 of 8

Question: Large lesions with dry scaly skin, no hair and absent sensations are seen typically in _____ leprosy

Answer: tuberculoid