Bacterial Skin Infections Practice Questions

Q: Erythema chronicum migrans is associated with which of the following conditions?

Lyme disease. ***Lyme disease*** - **Erythema chronicum migrans** (ECM) is the characteristic expanding annular rash seen in the early localized stage of **Lyme disease**. - It results from infection with **Borrelia burgdorferi**, transmitted by **Ixodes ticks**. *Glucagonoma* - This is a pancreatic neuroendocrine tumor that secretes **glucagon**. - It is classically associated with **necrolytic migratory erythema**, a distinct rash, not erythema chronicum migrans. *Gastrinoma* - A gastrinoma is a tumor that secretes **gastrin**, leading to **Zollinger-Ellison syndrome**, characterized by severe peptic ulcer disease. - It is not associated with skin rashes like erythema chronicum migrans. *Phaeochromocytoma* - This is a tumor of the adrenal medulla that secretes **catecholamines**, causing symptoms like hypertension, palpitations, and headaches. - It does not present with erythema chronicum migrans or other characteristic skin rashes.

Q: What is the best method of treatment for an ulnar nerve abscess in a case of leprosy?

Incision and drainage. ***Incision and drainage*** - An abscess, by definition, is a localized collection of **pus** that requires drainage for resolution and to prevent further tissue damage. - In the setting of an ulnar nerve abscess due to leprosy, surgical **incision and drainage** is the definitive treatment to remove the infected material and alleviate pressure on the nerve. *High doses of steroid* - Steroids are primarily used in leprosy to manage **nerve inflammation** and **reversal reactions**, not pre-formed pus collections like an abscess. - Using steroids alone for an abscess can suppress the immune response, potentially worsening the infection and delaying healing. *Thalidomide* - **Thalidomide** is most commonly used for severe type 2 leprosy reactions (**erythema nodosum leprosum**) due to its anti-inflammatory and immunomodulatory effects. - It does not have a role in directly treating a localized abscess, which requires physical drainage. *High dose of clofazimine* - **Clofazimine** is an anti-leprosy drug used as part of multi-drug therapy for treating the underlying *Mycobacterium leprae* infection. - While essential for treating leprosy, it will not resolve a pre-existing abscess, which is a collection of pus that needs to be mechanically drained.

Q: Which of the following drugs controls lepra reactions in leprosy?

Clofazimine. ***Clofazimine*** - **Clofazimine** is an anti-leprosy drug known for its **anti-inflammatory** and **immunomodulatory properties**, which help control **lepromin reactions** (specifically ENL or Type 2 lepra reactions) [1, 2]. - It stabilizes **mast cell membranes** and inhibits lymphocyte proliferation, thereby reducing the inflammatory response seen in lepromin reactions. *Dapsone* - **Dapsone** is a primary anti-leprosy drug that works by inhibiting **folate synthesis** in *Mycobacterium leprae* [2]. - While effective against the bacteria, it does not directly control the **immunological reactions** associated with leprosy, such as the lepromin reaction [1]. *Streptomycin* - **Streptomycin** is an antibiotic primarily used for **tuberculosis** and other bacterial infections, belonging to the **aminoglycoside** class. - It is **not a first-line drug** for leprosy and has no established role in controlling lepromin reactions. *Ethambutol* - **Ethambutol** is an anti-tuberculosis drug that inhibits **mycolic acid synthesis**, leading to impaired cell wall formation in mycobacteria. - It is **not used for treating leprosy** and therefore has no function in managing lepromin reactions.

Q: Apple jelly nodules are characteristic of which condition?

Lupus vulgaris. ***Correct: Lupus vulgaris*** **Apple-jelly nodules** are the pathognomonic sign of lupus vulgaris, a form of cutaneous tuberculosis. This characteristic appearance is revealed when suspected lesions are compressed with a **diascope (glass slide)**, demonstrating the underlying **granulomatous inflammation** with tuberculoid histology. *Incorrect: Cutaneous anaphylaxis* Cutaneous anaphylaxis presents with **rapid-onset urticaria (hives)** and angioedema, often with systemic symptoms like bronchospasm and hypotension. It does not produce slow-growing, persistent nodules or demonstrate the apple-jelly phenomenon on diascopy. *Incorrect: Erythroderma* Erythroderma is characterized by **diffuse erythema and scaling** affecting more than 90% of the body surface area. This widespread inflammatory condition does not form localized nodular lesions or exhibit the apple-jelly sign on diascopy. *Incorrect: Erythema nodosum* Erythema nodosum presents as **tender, erythematous, subcutaneous nodules**, typically on the lower extremities, representing panniculitis (inflammation of subcutaneous fat). These nodules are deep, painful, and do not blanch to reveal an apple-jelly appearance on diascopy.

Q: A 40-year-old female presented with numerous, non-itchy, erythematous, scaly papules (lesions) on the trunk, with a few oral white mucosal plaques and erosive lesions in the perianal area. The probable diagnosis is

Secondary syphilis. ***Secondary syphilis*** - **Erythematous, scaly papules** on the trunk (syphilitic roseola or papulosquamous lesions), **oral white mucosal plaques** (mucous patches), and **erosive lesions in the perianal area** (condylomata lata) are classic manifestations of secondary syphilis [1]. - The lesions are typically **non-itchy** and can appear widespread [1]. *Psoriasis* - Psoriasis typically presents with well-demarcated, **erythematous plaques covered with silvery scales**, often on extensor surfaces, and is usually itchy. - While psoriasis can affect mucous membranes, the specific combination of oral white plaques and perianal erosions is less characteristic than in secondary syphilis. *Lichen planus* - Lichen planus typically presents with **pruritic, purple, polygonal, planar papules** and often involves flexural surfaces. - Oral lichen planus can manifest as white reticular patterns (Wickham's striae) or erosions, but the widespread scaly papules on the trunk and perianal erosions observed here are not typical. *Disseminated candidiasis* - Disseminated candidiasis usually occurs in **immunocompromised individuals** and presents with widespread skin lesions, fever, and systemic symptoms. - The skin lesions are typically **macular, papular, or nodular and can be pustular**, but the description of scaly papules, oral white plaques, and perianal erosions is not characteristic of candidiasis.

Q: Which is the most common type of cutaneous tuberculosis?

Lupus vulgaris. ***Lupus vulgaris*** - This is the most common and persistent form of **cutaneous tuberculosis** in developed countries. - It often presents as **reddish-brown plaques** that expand peripherally, commonly affecting the head and neck. *Scrofuloderma* - This form typically arises from direct extension of tuberculosis from an underlying **lymph node** or bone abscess to the skin. - It presents as **cold abscesses** or ulcers with undermined edges and draining sinuses. *T.B. verruca cutis* - This is a **hyperkeratotic, warty lesion** that results from exogenous inoculation of *Mycobacterium tuberculosis* into the skin of an individual with high immunity. - It is often seen in pathologists or veterinarians who come into contact with infected tissues. *Erythema induratum* - Also known as **Bazin's disease**, it presents as recurrent, tender, **subcutaneous nodules** and plaques, typically on the calves. - It is usually associated with a systemic tuberculous focus and is considered a form of **panniculitis**.

Q: Which of the following conditions is associated with pseudo-buboes?

Granuloma inguinale. **Granuloma inguinale** - **Pseudo-buboes** are characteristic of granuloma inguinale and are subcutaneous granulomas that mimic the appearance of true buboes. - They are typically formed by **granulomatous tissue** in the inguinal region, not by inflamed lymph nodes as seen in true buboes. *Chancroid* - Chancroid is associated with true **buboes**, which are enlarged, painful, and often suppurative inguinal lymph nodes. - These buboes result from localized **lymphadenitis** due to *Haemophilus ducreyi* infection. *LGV* - **Lymphogranuloma venereum (LGV)** is known for causing characteristic **groove sign**, which involves deep inguinal lymphadenopathy that can lead to coalesced, firm, and matted nodes (true buboes) that may suppurate. - The buboes in LGV are typically **unilateral** and painful, evolving from initial infection with *Chlamydia trachomatis* serovars L1, L2, or L3. *All of the options* - This option is incorrect because while chancroid and LGV cause true buboes, only **granuloma inguinale** causes pseudo-buboes. - The distinction lies in the **etiology**; pseudo-buboes are granulomas, whereas true buboes are inflamed or suppurative lymph nodes.

Q: In multibacillary leprosy, what is the recommended follow-up examination period after adequate treatment?

5 years. ***5 years*** - Follow-up for **multibacillary leprosy** after adequate treatment is recommended for **5 years** to monitor for relapse. - This extended period is crucial due to the higher bacterial load and potential for late recurrence in multibacillary forms. *3 years* - A 3-year follow-up period is typically recommended for **paucibacillary leprosy**, which has a lower risk of relapse compared to multibacillary forms. - This duration is insufficient for multibacillary cases, as relapse can occur later. *10 years* - A 10-year follow-up period is generally considered excessive and not the standard recommendation for routine monitoring of treated leprosy cases. - While relapse can occur, 5 years is deemed sufficient for most multibacillary cases. *2 years* - A 2-year follow-up period is too short for multibacillary leprosy, as it significantly increases the risk of missing a potential relapse. - The latency for relapse in multibacillary leprosy can extend beyond this timeframe.

Q: Which of the following parts of the body is not affected by leprosy?

Ovary. ***Ovary*** - The **ovaries** are generally not affected by *Mycobacterium leprae* due to their internal location and higher core body temperature. - The bacterium thrives in **cooler temperatures**, which is why it typically affects superficial tissues and distal extremities. *Testes* - The **testes** are located externally and have a lower temperature, making them susceptible to *Mycobacterium leprae* infection. - Involvement can lead to severe damage, including **atrophy** and **infertility**. *Nasal mucosa* - The **nasal mucosa** is a common site of infection and a major portal of entry and exit for *Mycobacterium leprae*. - Early lesions can cause **nasal stuffiness** and progress to septal perforation and collapse of the nasal bridge. *Axilla* - Peripheral nerves in the **axilla**, such as the median, ulnar, and radial nerves, can be affected by leprosy. - Nerve involvement may lead to **sensory loss** and **motor weakness** in the upper limbs.

Question 1

Erythema chronicum migrans is associated with which of the following conditions?

Accepted Answer

Lyme disease

Answer

Glucagonoma

Answer

Gastrinoma

Answer

Phaeochromocytoma

Question 2

What is the best method of treatment for an ulnar nerve abscess in a case of leprosy?

Accepted Answer

Incision and drainage

Answer

High dose of clofazimine

Answer

Thalidomide

Answer

High doses of steroid

Question 3

A 12-year-old child presents with 4 lesions of leprosy on their back and four lesions on their left arm. What should be the treatment for this child?

Accepted Answer

Rifampicin 450 mg once monthly + Dapsone 50 mg daily + Clofazimine 50 mg alternate day

Answer

Rifampicin 300 mg once monthly + Dapsone 25 mg daily

Answer

Rifampicin 450 mg once monthly + Dapsone 50 mg daily

Answer

Rifampicin 600 mg once monthly + Dapsone 100 mg daily

Question 4

Which of the following drugs controls lepra reactions in leprosy?

Accepted Answer

Clofazimine

Answer

Dapsone

Answer

Streptomycin

Answer

Ethambutol

Question 5

Apple jelly nodules are characteristic of which condition?

Accepted Answer

Lupus vulgaris

Answer

Erythroderma

Answer

Erythema nodosum

Answer

Cutaneous anaphylaxis

Question 6

A 40-year-old female presented with numerous, non-itchy, erythematous, scaly papules (lesions) on the trunk, with a few oral white mucosal plaques and erosive lesions in the perianal area. The probable diagnosis is

Accepted Answer

Secondary syphilis

Answer

Psoriasis

Answer

Lichen planus

Answer

Disseminated candidiasis

Question 7

Which is the most common type of cutaneous tuberculosis?

Accepted Answer

Lupus vulgaris

Answer

Scrofuloderma

Answer

T.B. verruca cutis

Answer

Erythema induratum

Question 8

Which of the following conditions is associated with pseudo-buboes?

Accepted Answer

Granuloma inguinale

Answer

LGV

Answer

Chancroid

Answer

All of the options

Question 9

In multibacillary leprosy, what is the recommended follow-up examination period after adequate treatment?

Accepted Answer

5 years

Answer

3 years

Answer

10 years

Answer

2 years

Question 10

Which of the following parts of the body is not affected by leprosy?

Accepted Answer

Ovary

Answer

Nasal mucosa

Answer

Testes

Answer

Axilla

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

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