Bacterial Skin Infections — MCQs

Bacterial Skin Infections Indian Medical PG Practice Questions and MCQs

Question 191: Innumerable, small, normoesthetic and symmetrical skin lesions are present in which type of leprosy:

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

Explanation: ***Lepromatous*** - **Lepromatous leprosy** is characterized by a high bacterial load, leading to **innumerable, symmetrical, and poorly defined skin lesions** distributed bilaterally. - In **early lepromatous disease**, lesions may be **normoesthetic** (normal sensation) or only mildly hypesthetic before significant nerve damage develops. However, as the disease progresses, sensory loss becomes more apparent due to diffuse nerve involvement. - The combination of **innumerable + symmetrical + normoesthetic** lesions is most characteristic of **early lepromatous leprosy**. *Tuberculoid* - **Tuberculoid leprosy** typically presents with **few (1-5), well-demarcated, and often asymmetric** skin lesions. - These lesions show **marked sensory loss early** (anesthetic from onset) due to intense localized immune response and nerve damage. - Does not fit the description of innumerable, normoesthetic lesions. *Borderline tuberculoid* - **Borderline tuberculoid leprosy** features a **moderate number of lesions** (more than tuberculoid but not innumerable), which are usually well-defined. - Lesions show **noticeable sensory impairment** relatively early in the disease course. - Does not present with innumerable lesions. *Borderline lepromatous* - **Borderline lepromatous leprosy** has numerous lesions with varied morphology (macules, papules, plaques). - While extensive, sensory loss is usually **more pronounced** than in pure lepromatous leprosy due to more active nerve inflammation. - The combination of normoesthetic + innumerable + symmetrical is more specific to lepromatous rather than borderline lepromatous.

Question 192: Not a cutaneous manifestation of TB:

A. Erythema nodosum
B. Lupus pernio (Correct Answer)
C. Scrofuloderma
D. Lupus vulgaris

Explanation: ***Lupus pernio*** - **Lupus pernio** is characteristic of **sarcoidosis**, not tuberculosis. It typically presents as violaceous, indurated plaques on the face, especially the nose, cheeks, and ears. - Its presence usually indicates chronic and systemic sarcoidosis, differentiating it from tubercular skin manifestations. *Erythema nodosum* - **Erythema nodosum** can be a cutaneous manifestation of tuberculosis, often indicating an underlying immune response to the infection. - It presents as tender, red nodules, typically on the shins, reflecting a delayed hypersensitivity reaction. *Scrofuloderma* - **Scrofuloderma** is a direct cutaneous manifestation of tuberculosis, resulting from the extension of an underlying tuberculous infection (e.g., lymph nodes, bones) to the skin. - It involves painless, purplish nodules or plaques that ulcerate and discharge pus. *Lupus vulgaris* - **Lupus vulgaris** is a chronic and progressive form of cutaneous tuberculosis, characterized by reddish-brown plaques with an "apple-jelly" appearance on diascopy. - This manifestation occurs due to hematogenous or lymphatic spread of **Mycobacterium tuberculosis** to the skin in individuals with moderate immunity.

Question 193: Moth-eaten alopecia is seen with:

A. Cylindroma
B. Syphilis (Correct Answer)
C. Fungal infection
D. Leprosy

Explanation: ***Syphilis*** - **Moth-eaten alopecia** is a characteristic but non-specific finding in **secondary syphilis**, occurring due to immune-mediated inflammation targeting hair follicles. - It presents as patchy, non-scarring hair loss, predominantly on the scalp, eyebrows, and beard area. *Cylindroma* - **Cylindroma** is a benign adnexal tumor of the skin, typically presenting as multiple fleshy nodules on the scalp and face. - It is not associated with hair loss patterns like moth-eaten alopecia; rather, large lesions can cause pressure atrophy of hair follicles leading to localized hair loss. *Fungal infection* - **Fungal infections** of the scalp, such as tinea capitis, typically cause patches of **scaling, erythema, and broken hairs**, sometimes leading to **black dot tinea**. - While they can cause patchy hair loss, the description of "moth-eaten" is not the characteristic presentation for fungal infections. *Leprosy* - **Leprosy** can cause hair loss, particularly loss of the **lateral eyebrows** (madarosis) and body hair. - This hair loss is typically due to nerve damage leading to atrophy of hair follicles or direct granulomatous infiltration, not diffuse patchy "moth-eaten" alopecia.

Question 194: True about LGV ?

A. Bubos in 1st stage
B. Groove's sign in 3rd stage
C. Bleeding ulcer in 1st stage
D. Proctocolitis in 2nd stage (Correct Answer)

Explanation: ***Proctocolitis in 2nd stage*** - **Proctocolitis** can occur during the **secondary stage** of LGV, particularly in cases involving receptive anal intercourse where the primary inoculation occurs in the rectal mucosa. - Patients present with **bloody rectal discharge, pain, tenesmus, and diarrhea** due to lymphatic spread. - While chronic proctocolitis with strictures occurs in late-stage disease, acute proctocolitis is a manifestation of the secondary stage. *Groove's sign in 3rd stage* - **Groove sign** is actually characteristic of the **second stage**, not the third stage of LGV. - It represents the depression created when enlarged inguinal lymph nodes are separated by the inguinal ligament during the acute lymphadenopathy phase. - The third stage involves chronic complications like strictures and elephantiasis, not acute groove sign. *Bubos in 1st stage* - **Bubos** (painful, swollen regional lymph nodes) are characteristic of the **second stage** of LGV, not the first. - The first stage typically features a transient, small, painless papule or ulcer that often goes unnoticed. *Bleeding ulcer in 1st stage* - The primary lesion of LGV (first stage) is usually a **small, painless papule, vesicle, or ulceration** that is typically non-bleeding. - The primary lesion is often transient and may go unnoticed before lymphadenopathy develops.

Question 195: Asymmetrical nerve thickening with several hypoesthetic macules on skin indicates which stage of leprosy:

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

Explanation: ***Borderline tuberculoid (BT)*** - This stage is characterized by **prominent asymmetrical nerve thickening**, which is a hallmark feature distinguishing it from other borderline forms. - Patients typically present with **several (5-10 or more) asymmetrically distributed hypoesthetic macules or plaques** with well-defined borders, reflecting a strong but not complete cell-mediated immune response. - The combination of asymmetrical nerve involvement with multiple skin lesions is **classic for BT leprosy**, making it more stable than BB and with more lesions than pure TT. *Tuberculoid leprosy (TT)* - Characterized by **very few skin lesions (1-5)**, typically solitary or up to 5 well-demarcated hypopigmented or erythematous macules with complete anesthesia. - While asymmetrical nerve thickening occurs, the key differentiator is the **fewer number of lesions** - "several" macules suggests more than the typical TT presentation. *Borderline borderline (BB)* - Represents the **most unstable form** in the borderline spectrum, with numerous (often 10-30) moderately defined lesions. - Nerve involvement is present but **less prominently asymmetrical** than in BT, with features intermediate between tuberculoid and lepromatous poles. - The emphasis on "asymmetrical nerve thickening" in the question stem points away from BB toward the tuberculoid end of the spectrum. *Borderline lepromatous (BL)* - Marked by **many poorly defined lesions (often >30)** that are becoming more **symmetrically distributed**. - Nerve thickening is less prominent and **more symmetrical** than in BT or BB, reflecting a weaker cell-mediated immune response. - The asymmetrical pattern described in the question is not characteristic of BL.

Question 196: The hard chancre is seen in:

A. Chancroid
B. Granuloma inguinale
C. Syphilis (Correct Answer)
D. LGV

Explanation: ***Syphilis*** - The **hard chancre** is the characteristic lesion of **primary syphilis**, appearing at the site of infection. - It is typically a **painless, indurated ulcer with raised borders and a clean base**, which often heals spontaneously even without treatment. - Associated with **non-tender regional lymphadenopathy**, distinguishing it from the painful ulcers of chancroid. *Chancroid* - Chancroid is caused by *Haemophilus ducreyi* and presents with **soft, painful ulcers** (soft chancre) that bleed easily. - Unlike the hard chancre of syphilis, these lesions are multiple and often associated with **tender, suppurative lymphadenopathy**. *Granuloma inguinale* - This condition, caused by *Klebsiella granulomatis*, is characterized by **beefy-red, granulomatous lesions** that are typically painless and highly vascular. - It does not present with a chancre, but rather with progressive ulcerative lesions that can be destructive if untreated. *LGV* - **Lymphogranuloma venereum** (LGV) is caused by specific serovars of *Chlamydia trachomatis* and initially presents as a **transient, small, often unnoticed papule or ulcer**. - The most prominent feature of LGV is later development of significant **inguinal lymphadenopathy** (buboes) rather than a firm chancre.

Question 197: Which of the following is true regarding leprosy?

A. All deformity cases are MBL
B. Grenz zone is absent in Lepromatous leprosy
C. Any positive smear 1+ is MBL
D. MBL recommended treatment for 12 months duration (Correct Answer)

Explanation: ***MBL recommended treatment for 12 months duration*** - **Multibacillary leprosy (MBL)** requires a longer treatment regimen to effectively eradicate the higher bacterial load and prevent relapse. - The standard **WHO multidrug therapy (MDT)** for MBL involves **Rifampicin, Dapsone**, and **Clofazimine** for **12 months**. *All deformity cases are MBL* - Deformities can occur in both **Paucibacillary (PB)** and **Multibacillary (MBL)** leprosy, particularly due to **nerve damage** from inflammation or reactions. - The presence of deformity alone does not automatically classify a case as MBL; the **bacteriological index (BI)** and clinical presentation are crucial for classification. *Grenz zone is absent in Lepromatous leprosy* - The **Grenz zone** is a clear, uninvolved band of dermis separating the epidermis from the granulomatous infiltrates, and it is a characteristic histological feature often seen in **lepromatous leprosy**. - Its presence helps distinguish lepromatous leprosy from other dermal inflammatory conditions, as it indicates the spared superficial dermis. *Any positive smear 1+ is MBL* - While a positive smear indicates the presence of *Mycobacterium leprae*, the classification as **MBL** or **PB** depends on the **Bacteriological Index (BI)**. - A **BI of 2+ or more** at any site is typically used to classify a case as MBL, along with the number of skin lesions.

Question 198: Malignant pustules are seen in:

A. Anthrax (Correct Answer)
B. Pemphigus
C. Tularemia
D. Actinomycosis

Explanation: ***Anthrax*** - Cutaneous anthrax, caused by *Bacillus anthracis*, presents with a characteristic **painless ulcer with a black eschar** (malignant pustule) and surrounding edema. - This lesion evolves from a papule to a vesicle, then to a necrotic ulcer or "malignant pustule." *Pemphigus* - Pemphigus is an **autoimmune blistering disease** characterized by fragile blisters and erosions on the skin and mucous membranes. - It does not involve "malignant pustules" but rather flaccid bullae due to acantholysis. *Tularemia* - Tularemia, caused by *Francisella tularensis*, can present with an **ulceroglandular lesion** at the site of inoculation, but this is typically a single, painful ulcer with regional lymphadenopathy, not a "malignant pustule." - The ulcer is often clean-based and lacks the characteristic black eschar seen in anthrax. *Actinomycosis* - Actinomycosis is a bacterial infection caused by *Actinomyces species*, commonly presenting as **chronic, suppurative abscesses** that form sinus tracts. - The lesions are characterized by granulomas and "sulfur granules" in the pus, not "malignant pustules."

Question 199: What is the diagnosis of a child with a small abrasion over the face who develops fever with chills, induration, and fiery red swelling over the face extending to the ear?

A. Anthrax
B. Carbuncle
C. Cellulitis
D. Erysipelas (Correct Answer)

Explanation: ***Erysipelas*** - The presentation of **fiery red swelling** with well-demarcated, raised borders, rapidly extending from a small abrasion, especially on the face and involving the ear, is classic for erysipelas. - It also includes systemic symptoms like **fever and chills** and **induration**, which are characteristic of this superficial skin infection usually caused by **Streptococcus pyogenes**. *Anthrax* - Cutaneous anthrax typically presents with a papule that develops into a **vesicle**, then a painless ulcer with a distinctive **black eschar**, which is not described here. - While it can cause fever, the characteristic skin lesion is distinct from the red, spreading swelling seen in this case. *Carbuncle* - A carbuncle is a deep infection involving multiple hair follicles, presenting as a painful, interconnected lesion with **multiple draining sinuses**. - It is typically more localized, deeper, and pus-filled than the superficial, rapidly spreading, fiery red swelling described. *Cellulitis* - Cellulitis is a deeper infection of the dermis and subcutaneous fat, presenting with redness, warmth, and tenderness, but its borders are typically **less well-demarcated** and not as raised as in erysipelas. - While it can also occur on the face and cause systemic symptoms, the description of "fiery red" and "extending to the ear" with sharp borders makes erysipelas a more precise diagnosis.

Question 200: 'Coral red' color on Wood's lamp is seen in

A. Erythrasma (Correct Answer)
B. Pityriasis rosea
C. Tinea corporis
D. Tuberous sclerosis

Explanation: ***Erythrasma*** - Erythrasma, caused by *Corynebacterium minutissimum*, produces characteristic **porphyrins** that fluoresce **coral red** under Wood's lamp. - This specific fluorescence pattern is a key diagnostic feature for distinguishing erythrasma from other intertriginous dermatoses. *Pityriasis rosea* - This condition presents with a characteristic **herald patch** followed by smaller, oval, salmon-colored lesions in a "Christmas tree" pattern, without any specific fluorescence under Wood's lamp. - Its etiology is thought to be viral, and it does not involve the bacterial production of porphyrins. *Tinea corporis* - Also known as ringworm, tinea corporis is a dermatophyte infection that typically shows **no fluorescence** or sometimes a dull green fluorescence with some species (e.g., *Microsporum canis*), but never coral red. - Diagnosis is usually made by KOH direct microscopy of skin scrapings showing **hyphae and spores**. *Tuberous sclerosis* - This is a neurocutaneous disorder characterized by **ash-leaf spots** (hypopigmented macules) that may enhance as bright white under Wood's lamp due to loss of melanin. - It does not produce a coral red fluorescence and is a genetic condition, not an infection.

Practice by Chapter

Impetigo

Practice Questions

Folliculitis, Furuncles, and Carbuncles

Practice Questions

Ecthyma

Practice Questions

Erysipelas and Cellulitis

Practice Questions

Staphylococcal Scalded Skin Syndrome

Practice Questions

Necrotizing Fasciitis

Practice Questions

Cutaneous Tuberculosis

Practice Questions

Leprosy

Practice Questions

Lyme Disease

Practice Questions

Syphilis

Practice Questions

Antibiotic Resistance in Dermatology

Practice Questions

Prophylaxis and Management

Practice Questions

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