Tropical Dermatology — MCQs

The patient with leprosy had slightly erythematous, anesthetic plaques on the trunk and upper limbs. He was treated with paucibacillary multidrug therapy (PB-MDT) for 6 months. At the end of 6 months, he had persistent erythema and induration in the plaque. According to the World Health Organization (WHO) guidelines, what is the next recommended step of action for this patient?

Tropical Dermatology Indian Medical PG Practice Questions and MCQs

Question 61: Punched out lesion or inverted saucer appearance are characteristic of which type of leprosy?

A. Tuberculoid
B. Borderline tuberculoid
C. Lepromatous (Correct Answer)
D. Borderline lepromatous

Explanation: ***Lepromatous*** - **Punched-out lesions**, also known as "inverted saucer appearance," are characteristic of **lepromatous leprosy** due to extensive dermal infiltration and destruction by *Mycobacterium leprae*. - This form of leprosy involves a **weak cellular immune response** allowing widespread bacterial dissemination and visible skin lesions. *Tuberculoid* - Tuberculoid leprosy is characterized by a **strong cell-mediated immune response**, resulting in few, well-demarcated skin lesions with sensory loss. - It is typically **paucibacillary**, meaning few bacteria are present in the lesions, and does not cause punched-out or inverted saucer appearances. *Borderline tuberculoid* - Borderline tuberculoid leprosy presents with **moderate cell-mediated immunity** and a few skin lesions that are more numerous and less well-defined than in tuberculoid leprosy. - While it can be more extensive than tuberculoid, it typically does not exhibit the extensive tissue destruction leading to "punched-out" lesions characteristic of the lepromatous pole. *Borderline lepromatous* - Borderline lepromatous leprosy shows a **weak cellular immune response** and numerous, ill-defined lesions, often with varying sizes and shapes. - While it shares some features of lepromatous leprosy, the classic "punched-out" or "inverted saucer" appearance is more specifically associated with the widespread and uniform dermal infiltration of **full-blown lepromatous leprosy**.

Question 62: Type-II lepra reaction is most commonly found in:

A. BL
B. LL (Correct Answer)
C. BT
D. None of the options

Explanation: ***LL*** - **Type 2 lepra reactions (ENL)** are most commonly seen in the **lepromatous spectrum** of leprosy, particularly in **LL (lepromatous leprosy)** and sometimes in **BL (borderline lepromatous) leprosy**. - These reactions are an **immune complex-mediated hypersensitivity reaction** to M. leprae antigens, leading to acute inflammation. *BL* - While **Type II lepra reactions (ENL)** can occur in **borderline lepromatous (BL) leprosy**, they are **less frequent** and generally less severe than in LL. - Patients with BL leprosy are more prone to **Type I lepra reactions (reversal reactions)**, reflecting shifts in cell-mediated immunity. *BT* - **Borderline tuberculoid (BT) leprosy** patients primarily experience **Type I lepra reactions (reversal reactions)**, which are cell-mediated immune responses. - **Type II lepra reactions (ENL)** are generally **not seen** in the tuberculoid spectrum due to the robust cell-mediated immunity. *None of the options* - This option is incorrect because **LL (lepromatous leprosy)** is a well-established and common site for Type II lepra reactions. - The other options represent different classifications within the leprosy spectrum, and LL is indeed recognized for this specific reaction.

Question 63: Delhi boil refers to:

A. Solar Keratosis
B. Venereal ulcer
C. Malignant pustule
D. L. tropica sore (Correct Answer)

Explanation: ***L. tropica sore*** - Delhi boil is a common name for cutaneous **leishmaniasis**, specifically caused by **Leishmania tropica**. - This condition presents as a **skin lesion** or sore, primarily in endemic regions like Delhi. *Solar Keratosis* - Solar keratosis is a **precancerous skin lesion** caused by long-term exposure to ultraviolet (UV) radiation from the sun. - It presents as a **rough, scaly patch** on sun-exposed areas and is not associated with parasitic infection. *Venereal ulcer* - A venereal ulcer is a **genital sore** typically caused by sexually transmitted infections (STIs) such as syphilis, herpes, or chancroid. - These ulcers are localized to the genital area and have a different etiology and clinical presentation than Delhi boil. *Malignant pustule* - A malignant pustule is a term sometimes used historically to describe **anthrax skin lesions** due to their necrotic and often black center, but more generally refers to a pustular lesion with malignant or highly aggressive characteristics. - It is not a synonym for Delhi boil, which is a parasitic infection with a distinct clinical course and etiology.

Question 64: What factors contribute to the higher prevalence of tinea versicolor in tropical climates?

A. Increased sweating promotes fungal growth (Correct Answer)
B. Fungal spores are commonly found in tropical environments
C. UV exposure suppresses local skin immunity
D. Higher humidity levels facilitate fungal growth

Explanation: ***Increased sweating promotes fungal growth*** - **Malassezia**, the causative fungus of tinea versicolor, is **lipophilic** and thrives in warm, moist environments with increased sebum production - **Increased sweating** in tropical climates creates the optimal combination of **moisture, warmth, and lipid availability** on the skin surface, directly promoting fungal proliferation and conversion from commensal to pathogenic form - This is the **most direct and specific mechanism** linking tropical climates to tinea versicolor prevalence, as sweat provides both moisture and alters the skin pH favorable for *Malassezia* overgrowth *Incorrect: Fungal spores are commonly found in tropical environments* - *Malassezia* is a **normal commensal organism** found on human skin worldwide, not specifically in tropical environments - The organism's presence alone does not explain increased disease prevalence; rather, **environmental triggers** (heat, humidity, sweating) cause the transition from commensal to pathogenic state - Disease prevalence is determined by host and environmental factors, not mere presence of the organism *Incorrect: UV exposure suppresses local skin immunity* - While UV exposure can have immunosuppressive effects, this is **not the primary mechanism** for increased tinea versicolor in tropical regions - UV exposure actually makes the characteristic **hypopigmented lesions more noticeable** as surrounding skin tans while affected areas remain pale - There is no direct causal relationship between UV exposure and *Malassezia* overgrowth *Incorrect: Higher humidity levels facilitate fungal growth* - While humidity does contribute to favorable conditions for fungal growth, it is a **less specific factor** compared to increased sweating - Humidity alone without the accompanying **increased sweating, sebum production, and skin surface changes** is insufficient to fully explain the prevalence - The **combination of heat-induced sweating** with humidity is the key factor, making "increased sweating" the more comprehensive and direct answer

Question 65: In Ainhum, constriction develops usually at the level of the interphalangeal joint of which toe?

A. Great toe
B. 2nd toe
C. 4th toe
D. 5th toe (Correct Answer)

Explanation: ***5th toe*** - **Ainhum** is a condition characterized by progressive concentric constrictions, typically leading to autoamputation. - It most commonly affects the **fifth digit of the foot** (little toe), at the level of the **interphalangeal joint**. - The characteristic constriction band typically begins on the **plantar-medial aspect** of the fifth toe. *Great toe* - While other toes can be affected, the great toe is less commonly involved in Ainhum. - The disease shows a strong predilection for the lateral digits, particularly the fifth toe. *2nd toe* - The second toe is not the most common digit for the constriction band to develop in Ainhum. - The progression of the disease occurs more frequently in the outermost digits. *4th toe* - While the fourth toe can occasionally be affected, it is much less common than the fifth toe. - Ainhum demonstrates a characteristic pattern favoring the fifth toe in over 90% of cases.

Question 66: In which condition is an ulceronecrotic nodule typically observed?

A. Lucio's leprosy (Correct Answer)
B. Lepromatous leprosy
C. Indeterminate leprosy
D. Histoid leprosy

Explanation: ***Lucio's leprosy*** - This is a rare, diffuse variant of **lepromatous leprosy** characterized by widespread, diffuse infiltration of the skin without distinct nodules. - The distinctive feature is the occurrence of **necrotizing vasculitis**, leading to painful, irregular ulcers and scars, known as **Lucio phenomenon** or erythema necroticans. *Lepromatous leprosy* - Characterized by **multiple, symmetrical nodules**, plaques, and diffuse infiltration, but typically without the profound ulceronecrotic changes seen in Lucio's leprosy. - The immune response is weak, leading to high bacterial load and widespread involvement, but usually not spontaneous ulceration. *Indeterminate leprosy* - This is an **early, undifferentiated form** of leprosy, characterized by a single or a few hypopigmented or erythematous macules. - Distinct nodules or ulceronecrotic lesions are not a feature of indeterminate leprosy, as the disease has not yet progressed to develop specific clinical manifestations. *Histoid leprosy* - A rare variant of lepromatous leprosy that presents with **cutaneous nodules** and papules that often resemble dermatofibromas or xanthomas. - These nodules are firm, smooth, and have a unique histological appearance, but they do not typically undergo spontaneous ulceronecrotic changes like those in Lucio's leprosy.

Question 67: 26-year-old man from Bihar presents with erythematous papules on the face and back of the neck, which are hypopigmented and normoaesthetic, with no nerve thickening. A history of prolonged fever in childhood is present. What is the diagnosis?

A. Tuberculoid leprosy
B. Lepromatous leprosy
C. Lupus vulgaris
D. Dermal leishmaniasis (PKDL) (Correct Answer)

Explanation: ***Dermal leishmaniasis (PKDL)*** - PKDL presents with **erythematous papules** on the face and neck, which are **hypopigmented and normoaesthetic** (intact sensation), fitting the patient's description perfectly. - A history of **prolonged fever in childhood** in Bihar is highly suggestive of prior **visceral leishmaniasis (kala-azar)**, after which PKDL typically develops (months to years post-treatment). - The **absence of nerve thickening** and **normal sensation** are key features distinguishing PKDL from leprosy. - Bihar is an **endemic area** for visceral leishmaniasis in India. *Tuberculoid leprosy* - Characterized by **hypopigmented, anaesthetic patches** with **thickened nerves** - both features are absent in this case. - The **normoaesthetic** nature of lesions here rules out tuberculoid leprosy. - Lesions are typically **well-demarcated** and few in number. *Lepromatous leprosy* - Involves widespread, symmetrical lesions that are often **erythematous nodules** or **diffuse infiltrations**, with multiple nerve involvements. - Would show **nerve thickening** and eventual sensory loss, which are not present here. - The clinical picture does not match lepromatous leprosy. *Lupus vulgaris* - A form of **cutaneous tuberculosis** presenting as red-brown plaques with an **"apple-jelly" appearance** on diascopy. - While it can occur on the face, there is no history of fever or connection to visceral leishmaniasis. - The morphology (papules vs plaques) and epidemiological context favor PKDL.

Question 68: A 35-year-old female presented with multiple inverted saucer-shaped ulcers over the body, with sensations near normal. The SSS test was positive, and the lepromin test was negative. What is the most appropriate management for this patient?

A. T.Rifampicin 600 mg and T.Clofazimine 300 mg once a month, T.Clofazimine 100 mg daily, and T.Dapsone 100 mg daily for 12 months.
B. T.Rifampicin 600 mg and T.Clofazimine 300 mg once a month, T.Clofazimine 50 mg daily, and T.Dapsone 100 mg daily for 6 months.
C. T.Rifampicin 600 mg and T.Clofazimine 300 mg once a month, T.Clofazimine 50 mg daily, and T.Dapsone 1000 mg daily for 12 months.
D. T.Rifampicin 600 mg and T.Clofazimine 300 mg once a month, T.Clofazimine 50 mg daily, and T.Dapsone 100 mg daily for 12 months. (Correct Answer)

Explanation: ***Correct WHO MDT-MB regimen (Rifampicin 600 mg + Clofazimine 300 mg monthly, Clofazimine 50 mg daily, Dapsone 100 mg daily for 12 months)*** - The clinical presentation (multiple inverted saucer-shaped ulcers, near normal sensations, positive **SSS test**, negative **lepromin test**) is characteristic of **lepromatous leprosy** (multibacillary leprosy). - The standard WHO-recommended multidrug therapy (MDT) for multibacillary leprosy is **Rifampicin 600 mg once monthly**, **Clofazimine 300 mg once monthly** plus **50 mg daily**, and **Dapsone 100 mg daily for 12 months**. - This regimen ensures adequate bacterial clearance and prevents relapse in multibacillary cases. *Incorrect: Clofazimine 100 mg daily dose* - The daily dose of **Clofazimine** (100 mg) is incorrect, as the standard daily dose for multibacillary leprosy is **50 mg**, not 100 mg. - While other components (Rifampicin, Dapsone doses) and 12-month duration are correct, the incorrect daily clofazimine dose makes this option unsuitable. *Incorrect: 6-month duration* - The duration of treatment for multibacillary leprosy is **12 months**, not 6 months. - A 6-month regimen is indicated for **paucibacillary leprosy** only. - Inadequate treatment duration increases the risk of **relapse and drug resistance** in multibacillary cases. *Incorrect: Dapsone 1000 mg daily dose* - The daily dose of **Dapsone** (1000 mg) is significantly higher than the recommended **100 mg daily**, risking severe toxicity. - High doses of Dapsone can lead to **hemolytic anemia**, **methemoglobinemia**, and other serious adverse effects.

Question 69: The patient with leprosy had slightly erythematous, anesthetic plaques on the trunk and upper limbs. He was treated with paucibacillary multidrug therapy (PB-MDT) for 6 months. At the end of 6 months, he had persistent erythema and induration in the plaque. According to the World Health Organization (WHO) guidelines, what is the next recommended step of action for this patient?

A. Stop antileprosy treatment (Correct Answer)
B. Continue PB-MDT till erythema subsides
C. Biopsy the lesion to document activity
D. Continue dapsone alone for another 6 months

Explanation: ***Stop antileprosy treatment*** - According to **WHO guidelines**, paucibacillary multidrug therapy (PB-MDT) has a **fixed duration of 6 months**, after which treatment should be **stopped regardless of clinical appearance** of the lesions. - The persistent erythema and induration after completing 6 months of PB-MDT represent a **Type 1 lepra reaction (reversal reaction)**, which is an **immunological phenomenon**, not active disease requiring continued antimicrobial therapy. - **Type 1 reactions** should be managed with **corticosteroids (prednisolone 40-60 mg/day)**, not by prolonging MDT, as reactions are inflammatory rather than infectious in nature. - Continuing MDT beyond the recommended duration does **not prevent or treat lepra reactions** and unnecessarily exposes the patient to **drug toxicity and side effects**. *Continue PB-MDT till erythema subsides* - This is **not recommended by WHO guidelines**, which specify a **fixed duration** for PB-MDT (6 months) that should not be extended based on residual erythema or induration. - Persistent inflammation after completing treatment represents a **lepra reaction**, which is managed with **corticosteroids**, not continued MDT. - Extending MDT beyond 6 months for PB cases has no proven benefit and increases risk of **adverse drug reactions** without improving outcomes. *Biopsy the lesion to document activity* - While biopsy could provide histological information, the clinical scenario clearly describes a **Type 1 lepra reaction** occurring at the end of treatment. - The **diagnosis of Type 1 reaction is clinical**, based on erythema, induration, and tenderness in existing lesions after or during treatment. - Biopsy would only delay appropriate management with **corticosteroids** and is not necessary when clinical features are typical. *Continue dapsone alone for another 6 months* - **Monotherapy with dapsone** is absolutely contraindicated in leprosy management due to high risk of **drug resistance**. - After completing the fixed 6-month PB-MDT regimen, **no further antimicrobial therapy is indicated** for paucibacillary leprosy. - The persistent inflammation requires management of the **lepra reaction with corticosteroids**, not continued antimicrobial therapy.

Practice by Chapter

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