Bacterial Skin Infections Practice Questions

Q: A 24-year-old male came to OPD with brownish itchy patches in axilla, Wood's lamp examination shows "coral red" fluorescence. Most likely diagnosis is:

Erythrasma. ***Erythrasma*** - Erythrasma is a superficial bacterial infection caused by *Corynebacterium minutissimum*, presenting as **brownish, itchy patches** in intertriginous areas like the **axilla**. - The pathognomonic finding is a characteristic **"coral red" fluorescence** under Wood's lamp due to the production of porphyrin. *Tinea corporis* - This is a fungal infection (ringworm) of the body, characterized by **annular lesions** with raised, erythematous borders and central clearing. - While it can be itchy, it typically does not produce **coral red fluorescence** under Wood's lamp; instead, a fungal infection might show no fluorescence or a dull green-yellow hue in some cases. *Tinea cruris* - This is a fungal infection of the groin, commonly known as "jock itch," presenting as an **erythematous, scaling rash** with well-demarcated borders. - Similar to tinea corporis, it is caused by dermatophytes and does not exhibit **coral red fluorescence** under Wood's lamp. *Hidradenitis suppurativa* - This is a chronic inflammatory skin condition characterized by **recurrent abscesses, nodules, and sinus tracts** in areas with apocrine sweat glands, such as the axilla and groin. - While it affects the axilla, its presentation with painful nodules and scarring is distinct from the described brownish patches, and it does not demonstrate **coral red fluorescence**.

Q: Lupus vulgaris is:

Tuberculosis of skin. ***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.

Q: What is the treatment for single lesion leprosy?

Rifampicin, ofloxacin, and minocycline. ***Rifampicin, ofloxacin, and minocycline*** - This combination is the recommended **single-dose multidrug therapy (SDMDT)** for **single lesion paucibacillary leprosy**, which is classified as *single-lesion tuberculoid leprosy*. - Administered as a single, supervised dose, this regimen aims to simplify treatment and improve compliance for this specific presentation. *Dapsone and rifampicin* - This is the traditional regimen for **paucibacillary leprosy**, but it is typically given over **6 months**, not as a single dose for a single lesion. - It lacks the additional agents that provide the efficacy for a single-dose treatment in specific cases. *Rifampicin, ofloxacin, and dapsone* - While dapsone is part of standard multidrug therapy, it is not used in combination with ofloxacin and minocycline for **single-lesion leprosy** as a single dose. - This specific combination is not a recognized or recommended regimen for any type of leprosy. *Dapsone, clofazimine, and ofloxacin* - **Dapsone** and **clofazimine** are components of the **multibacillary leprosy** regimen, typically given with rifampicin for a longer duration (12 months). - Ofloxacin is not typically combined with dapsone and clofazimine in standard regimens for either paucibacillary or multibacillary leprosy.

Q: Characteristic of primary chancre:

Painless punched out ulcer. ***Painless punched out ulcer*** - A primary chancre of **syphilis** typically presents as a **painless ulcer**. - Its appearance is often described as **punched out**, with sharp, raised borders and a clean base. *Painful ulcer with undermined edges* - This description is more characteristic of a **chancroid**, caused by *Haemophilus ducreyi*. - Chancroids are typically **painful** and often have **undermined edges** with a grey or necrotic base. *Painless ulcer with rolled edges* - While a primary chancre is painless, it does not typically have **rolled edges**. - **Rolled edges** are more often associated with **basal cell carcinoma**, a cancerous lesion. *Painful punched out ulcer* - The combination of a **painful** ulcer that is **punched out** is not characteristic of a primary chancre due to syphilis. - Primary chancres are classically **painless**.

Q: The standard regimen for satisfactory treatment of paucibacillary leprosy consists of

Dapsone and rifampicin for 6 months. ***Dapsone and rifampicin for 6 months*** - The standard **multidrug therapy (MDT)** for **paucibacillary (PB) leprosy** involves a combination of **Dapsone** and **Rifampicin**. - This regimen is administered for a duration of **6 months** to achieve satisfactory treatment and prevent resistance. *Dapsone alone for 12 months* - **Monotherapy** with Dapsone is **not recommended** for leprosy due to the high risk of developing **drug resistance**. - While Dapsone is a component, it must be combined with other drugs. *Dapsone and ethionamide for 12 months* - **Ethionamide** is typically used as a second-line drug, primarily in cases of **multidrug-resistant leprosy** or specific treatment failures. - It is not part of the standard initial regimen for paucibacillary leprosy. *Dapsone and clofazimine for 6 months* - The combination of **Dapsone and Clofazimine** is part of the standard regimen for **multibacillary (MB) leprosy**, not paucibacillary. - While Clofazimine is effective, it is withheld for PB leprosy to minimize drug burden and side effects, as these patients have a lower bacterial load.

Q: Thalidomide is drug of choice for -

Lepra II reaction. ***Lepra II reaction*** - **Thalidomide** is highly effective in treating **erythema nodosum leprosum (ENL)**, also known as Lepra II reaction. - It works by modulating the immune response, reducing the severe inflammatory symptoms. *Nerve abscess* - **Nerve abscesses** in leprosy usually require surgical drainage and appropriate antibiotic treatment, not thalidomide. - They represent a localized collection of pus within a nerve, often associated with a **Type I reaction**. *Lepra I reaction* - **Type I reactions** (reversal reactions) are typically managed with corticosteroids to reduce inflammation and prevent nerve damage. - Thalidomide is not the primary treatment for these reactions, as their underlying immunological mechanism differs from Type II reactions. *Both* - Thalidomide is specific to **Lepra II reactions (ENL)** and is not the drug of choice for nerve abscesses or Lepra I reactions. - Treating both conditions with thalidomide would be inappropriate given their distinct pathologies and treatment protocols.

Q: Skin TB which involves skin after involving lymph nodes –

Scrofuloderma. ***Scrofuloderma*** - This form of **cutaneous tuberculosis** results from the direct extension of underlying **tuberculosis** affecting structures such as **lymph nodes**, bones, or joints to the overlying skin. - The skin lesion often appears as an **ulcer** or **sinus tract** with **purulent discharge**, reflecting the underlying infection communicating with the surface. *Lupus erythematosus* - Lupus erythematosus is a systemic autoimmune disease that can affect the skin, but it is not a form of **tuberculosis**. - Skin manifestations range from acute malar rashes to chronic discoid lesions, which are distinct from **tuberculous ulcers**. *Lupus pernio* - This is a cutaneous manifestation of **sarcoidosis**, characterized by **violaceous plaques** and nodules typically on the face (nose, cheeks), ears, and fingers. - It is not a form of **tuberculosis** and does not result from the direct extension of an underlying local infection. *Lupus vulgaris* - This is a chronic and progressive form of **cutaneous tuberculosis** that directly affects the skin in individuals with high immunity to the **tubercle bacillus**. - It presents as **reddish-brown plaques** with an **apple-jelly** nodule appearance on diascopy, and does not typically arise from an underlying lymph node infection extending to the skin.

Q: Features of secondary syphilis are: a) Condyloma accuminata b) Condyloma lata c) Mulberry/Moon's molars d) Lesions over palms/soles

bd. ***bd*** - **Condyloma lata** are moist, wart-like lesions that appear in intertriginous areas (e.g., anogenital region, axillae) and are highly infectious manifestations of secondary syphilis [1]. - **Lesions over palms/soles** are classic mucocutaneous manifestations of secondary syphilis, characterized by a non-pruritic, maculopapular rash [1]. *ad* - **Condyloma accuminata** are genital warts caused by the **Human Papillomavirus (HPV)**, not syphilis. - While lesions over palms/soles are a feature of secondary syphilis, the inclusion of condyloma acuminata makes this option incorrect. *ac* - **Condyloma accuminata** are caused by **HPV**, making this option incorrect for syphilis. - **Mulberry/Moon's molars** are a feature of **congenital syphilis**, not secondary syphilis [1]. *bc* - While **condyloma lata** are characteristic of secondary syphilis, **Mulberry/Moon's molars** are a stigmata of **congenital syphilis** [1]. - This option incorrectly combines features of secondary and congenital syphilis.

Q: Ridley-Jopling classification includes all except:

Neuritic. ***Neuritic*** - The Ridley-Jopling classification focuses on the **polar spectrum** of immune response in leprosy and doesn't include "neuritic" as a distinct classification type within this framework. - While nerve involvement is a hallmark of leprosy, the classification system categorizes patients based on their **clinical and histopathological features** reflecting the host's immune response to *Mycobacterium leprae*. *Tuberculoid* - This is one of the **five main classifications** in the Ridley-Jopling spectrum, representing the pole with a strong cell-mediated immune response. - Characterized by **few lesions**, well-demarcated, and often associated with significant **nerve damage**. *Borderline borderline* - This represents the **mid-spectrum** between tuberculoid and lepromatous poles, indicating an unstable immune response. - Patients in this category often show features of both more resistant and more susceptible forms of the disease, with **moderately numerous lesions** and variable nerve involvement. *Lepromatous leprosy* - This is the other **polar extreme** of the Ridley-Jopling classification, characterized by a weak or absent cell-mediated immune response. - Patients have **numerous, diffuse lesions** with high bacterial loads and widespread nerve damage, though less severe clinically than tuberculoid leprosy initially.

Q: A 35 years old male came with a progressive plaque over buttock for the last 2 years. The plaque is annular in shape with scarring in centre. Most likely diagnosis is:

Lupus vulgaris. ***Lupus vulgaris*** - This is a chronic and progressive form of **cutaneous tuberculosis** characterized by plaques that often have a distinctive **annular shape** and can lead to **scarring, atrophy**, or even **ulceration** in the center. - The slow, progressive nature over two years, with a central scar, aligns well with the typical presentation of lupus vulgaris, especially in areas like the buttocks or face. *Kala azar* - Also known as **visceral leishmaniasis**, it primarily affects internal organs and is characterized by **fever, hepatosplenomegaly**, and **pancytopenia**. - While it can present with dermal lesions (post-kala azar dermal leishmaniasis), these are typically **nodular** or **macular**, not annular plaques with central scarring in the initial presentation. *Borderline leprosy* - Leprosy presents with diverse skin lesions, but these are typically characterized by **hypopigmented** or **erythematous patches/plaques** with **sensory loss**. - The lesions of borderline leprosy are generally not described as annular plaques with prominent central scarring in the absence of other typical neurological features. *Tinea corporis* - This is a superficial fungal infection of the skin, commonly presenting as an **annular (ring-shaped)** lesion with an **erythematous, scaly border** and central clearing. - However, tinea corporis rarely causes **significant scarring** and chronic, progressive plaques over two years are atypical for this condition, which is usually more acute and responsive to antifungal treatment.

Question 1

A 24-year-old male came to OPD with brownish itchy patches in axilla, Wood's lamp examination shows "coral red" fluorescence. Most likely diagnosis is:

Accepted Answer

Erythrasma

Answer

Tinea corporis

Answer

Tinea cruris

Answer

Hidradenitis suppurativa

Question 2

Lupus vulgaris is:

Accepted Answer

Tuberculosis of skin

Answer

Squamous cell carcinoma

Answer

Basal cell carcinoma

Answer

Lupus erythematosus

Question 3

What is the treatment for single lesion leprosy?

Accepted Answer

Rifampicin, ofloxacin, and minocycline

Answer

Dapsone and rifampicin

Answer

Rifampicin, ofloxacin, and dapsone

Answer

Dapsone, clofazimine, and ofloxacin

Question 4

Characteristic of primary chancre:

Accepted Answer

Painless punched out ulcer

Answer

Painful ulcer with undermined edges

Answer

Painless ulcer with rolled edges

Answer

Painful punched out ulcer

Question 5

The standard regimen for satisfactory treatment of paucibacillary leprosy consists of

Accepted Answer

Dapsone and rifampicin for 6 months

Answer

Dapsone alone for 12 months

Answer

Dapsone and ethionamide for 12 months

Answer

Dapsone and clofazimine for 6 months

Question 6

Thalidomide is drug of choice for -

Accepted Answer

Lepra II reaction

Answer

Nerve abscess

Answer

Lepra I reaction

Answer

Both

Question 7

Skin TB which involves skin after involving lymph nodes –

Accepted Answer

Scrofuloderma

Answer

Lupus erythematosus

Answer

Lupus pernio

Answer

Lupus vulgaris

Question 8

Features of secondary syphilis are: a) Condyloma accuminata b) Condyloma lata c) Mulberry/Moon's molars d) Lesions over palms/soles

Accepted Answer

bd

Answer

ad

Answer

ac

Answer

bc

Question 9

Ridley-Jopling classification includes all except:

Accepted Answer

Neuritic

Answer

Tuberculoid

Answer

Borderline borderline

Answer

Lepromatous leprosy

Question 10

A 35 years old male came with a progressive plaque over buttock for the last 2 years. The plaque is annular in shape with scarring in centre. Most likely diagnosis is:

Accepted Answer

Lupus vulgaris

Answer

Kala azar

Answer

Borderline leprosy

Answer

Tinea corporis

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

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