Tropical Dermatology Practice Questions

Q: Single skin lesion is seen in which type of leprosy -

TT. ***TT*** - **Tuberculoid leprosy (TT)** is characterized by a strong cell-mediated immune response, leading to a **single, well-demarcated skin lesion** with clear borders and sensory loss. - The few bacilli present are kept localized, preventing widespread dissemination and multiple lesions. *LL* - **Lepromatous leprosy (LL)** is associated with a weak cell-mediated immune response, resulting in **numerous, poorly defined lesions**, nodules, and widespread infiltration. - The high bacillary load leads to systemic involvement and many lesions rather than a single one. *BL* - **Borderline lepromatous (BL)** leprosy is an unstable form with features between borderline tuberculoid and lepromatous, presenting with **multiple, widespread lesions** often with varying sizes and sensory loss. - While skin lesions are present, they are typically numerous and polymorphic, not a single lesion. *BT* - **Borderline tuberculoid (BT)** leprosy presents with **few to several skin lesions**, which are usually smaller, less well-defined, and more numerous than in TT leprosy. - Although closer to TT, it generally involves more than one lesion and exhibits less pronounced sensory loss compared to the single, anesthetic lesion of TT.

Q: Multiple hypoaesthetic, hypopigmented macules on right lateral forearm with numerous acid-fast bacilli is indicative of:

Lepromatous leprosy. ***Lepromatous leprosy*** - The hallmark feature is **numerous acid-fast bacilli (AFB)** in skin smears, indicating a **high bacterial load** characteristic of lepromatous leprosy (bacterial index 4-6+). - Lepromatous leprosy is **multibacillary** with **poor cell-mediated immunity**, allowing uncontrolled bacterial multiplication (10⁶-10⁹ bacilli per gram of tissue). - While typically presenting with **widespread, symmetrical lesions**, early lepromatous leprosy can present with **multiple hypopigmented macules** before progressing to diffuse infiltration. - **Sensory loss** may be present but is typically **less pronounced** initially compared to tuberculoid leprosy, as nerve damage occurs gradually. *Borderline leprosy* - Represents the **unstable middle spectrum** (BT, BB, BL) with **moderately impaired immunity** and **variable bacterial load**. - Borderline tuberculoid (BT) has **few AFB**, borderline lepromatous (BL) has **moderate AFB**, but the term "numerous AFB" more specifically indicates lepromatous leprosy. - Lesions are typically **asymmetrical** with variable sensory loss depending on the subtype. *Tuberculoid leprosy* - Characterized by **paucibacillary disease** with **strong cell-mediated immunity** that effectively contains bacterial proliferation. - Skin smears show **few or no detectable AFB** (bacterial index 0-1+) due to robust immune response. - Presents with **few well-defined lesions (1-5)** with **marked sensory loss** and thickened nerves. *Indeterminate leprosy* - The **earliest stage** of leprosy, presenting as a **single hypopigmented or erythematous macule** with minimal sensory changes. - Shows **few or no AFB** on skin smears and may evolve into any form of leprosy or resolve spontaneously. - Not consistent with multiple lesions and numerous bacilli.

Q: Type-II lepra reaction is most commonly found in:

LL. ***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.

Q: Most common nerve affected in leprosy

Posterior tibial. **Posterior tibial** - The **posterior tibial nerve** is the **most commonly affected nerve** in leprosy, particularly in the lower extremities. - Due to its superficial course and susceptibility to **cooler temperatures**, it is an ideal site for *Mycobacterium leprae* replication, leading to nerve damage. *Ulnar* - The **ulnar nerve** is frequently affected, particularly at the **elbow (cubital tunnel)**, leading to sensory and motor deficits in the hand. - While common, it is generally considered the **second most affected nerve** after the posterior tibial nerve. *Median* - The **median nerve** can be involved at the wrist in the **carpal tunnel**, causing sensory and motor deficits in the thumb, index, and middle fingers. - However, it is less commonly and less severely affected than the ulnar or posterior tibial nerves in leprosy. *Facial* - The **facial nerve** can be affected in leprosy, leading to **facial paresis or paralysis**, particularly in cases of lepromatous leprosy. - While it can cause significant disfigurement, it is not the most commonly affected nerve overall.

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

5th toe. ***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.

Q: In which condition is an ulceronecrotic nodule typically observed?

Lucio's leprosy. ***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 1

Single skin lesion is seen in which type of leprosy -

Accepted Answer

TT

Answer

LL

Answer

BL

Answer

BT

Question 2

Multiple hypoaesthetic, hypopigmented macules on right lateral forearm with numerous acid-fast bacilli is indicative of:

Accepted Answer

Lepromatous leprosy

Answer

Borderline leprosy

Answer

Tuberculoid leprosy

Answer

Indeterminate leprosy

Question 3

Type-II lepra reaction is most commonly found in:

Accepted Answer

LL

Answer

BL

Answer

BT

Answer

None of the options

Question 4

Most common nerve affected in leprosy

Accepted Answer

Posterior tibial

Answer

Median

Answer

Facial

Answer

Ulnar

Question 5

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

Accepted Answer

5th toe

Answer

Great toe

Answer

2nd toe

Answer

4th toe

Question 6

In which condition is an ulceronecrotic nodule typically observed?

Accepted Answer

Lucio's leprosy

Answer

Lepromatous leprosy

Answer

Indeterminate leprosy

Answer

Histoid leprosy

Question 7

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?

Accepted Answer

Stop antileprosy treatment

Answer

Continue PB-MDT till erythema subsides

Answer

Biopsy the lesion to document activity

Answer

Continue dapsone alone for another 6 months

Tropical Dermatology — MCQs

Tropical Dermatology — MCQs

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