Bacterial Skin Infections Practice Questions

Q: Lucio reaction is seen in which of the following conditions?

Leprosy. **Explanation:** **Lucio reaction** (also known as *phenomenon of Lucio*) is a rare, severe, and life-threatening type of reactional state specifically seen in patients with **Diffuse Lepromatous Leprosy (DLL)**. It is most commonly associated with the non-nodular, "pure and primitive" diffuse form of leprosy (Lucio-Latapi leprosy), particularly in patients from Mexico and Central America. **Why Leprosy is correct:** The underlying mechanism is a **necrotizing vasculitis** caused by direct invasion of the endothelial cells of blood vessels by *Mycobacterium leprae*. This leads to vascular occlusion, tissue infarction, and subsequent large, jagged, "punched-out" necrotic ulcers. Unlike Type 2 Lepra reactions (Erythema Nodosum Leprosum), Lucio reaction does not typically present with systemic fever or constitutional symptoms initially, but focuses on cutaneous infarcts. **Why other options are incorrect:** * **Tuberculosis:** While TB can cause various skin manifestations (like Lupus Vulgaris or Scrofuloderma), it does not manifest as Lucio reaction. * **Syphilis:** Secondary syphilis presents with a generalized maculopapular rash (including palms and soles) or Condyloma lata, but not necrotizing vasculitis of this type. * **Lymphogranuloma venereum (LGV):** Caused by *Chlamydia trachomatis*, it primarily affects the lymphatics (buboes) and anogenital area, not the systemic vascular system. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Standard WHO MDT for Leprosy; however, systemic corticosteroids and wound care are vital. Thalidomide is generally **not** effective for Lucio reaction (unlike ENL). * **Histopathology:** Shows massive infiltration of the dermis and blood vessel walls by Acid-Fast Bacilli (AFB). * **Triad of Lucio Leprosy:** Diffuse skin infiltration, alopecia of eyebrows/eyelashes, and the Lucio phenomenon.

Q: The primary lesion of syphilis, the Hunterian chancre, is characterized by which of the following features, EXCEPT?

Bleeding. The primary lesion of syphilis, the **Hunterian chancre**, is the hallmark of primary syphilis, appearing approximately 3 weeks after inoculation with *Treponema pallidum*. [1] ### **Why "Bleeding" is the Correct Answer** A classic syphilitic chancre is characterized by its **clean base**. Unlike many other genital ulcers, it does **not bleed easily** on manipulation. If the surface is scraped, it typically exudes a clear, serous fluid rich in treponemes (visible on dark-field microscopy) rather than blood. ### **Explanation of Other Options** * **Painless (Option A):** This is a defining feature. The chancre is characteristically non-tender unless secondary bacterial infection occurs. [1] * **Indurated (Option B):** The term "Hunterian" refers to the button-like, firm, or cartilaginous consistency (induration) of the ulcer's base and margins. * **Shallow Ulcer (Option C):** The lesion typically begins as a papule that erodes into a shallow, well-demarcated ulcer with a "punched-out" appearance. ### **High-Yield Clinical Pearls for NEET-PG** * **Lymphadenopathy:** Primary syphilis is associated with **painless, non-suppurative, rubbery** regional lymphadenopathy (usually bilateral inguinal). [1] * **Diagnosis:** The gold standard for primary syphilis is **Dark-field microscopy**. Serological tests (VDRL/RPR) may be negative in the first 1–2 weeks of the chancre's appearance. * **Differential Diagnosis:** * **Chancroid (Haemophilus ducreyi):** Painful, soft, and **bleeds easily** (the opposite of syphilis). * **Herpes Simplex:** Multiple, painful, superficial vesicles/ulcers. * **Treatment:** The drug of choice is **Benzathine Penicillin G** (2.4 million units IM, single dose).

Q: A 12-year-old boy presents with a white facial lesion that has grown noticeably large. Examination reveals hypoesthesia over the lesion and a smooth surface. What is the likely diagnosis?

Indeterminate leprosy. **Explanation:** The clinical presentation of a **hypopigmented (white) lesion** with **hypoesthesia** (loss of sensation) in a young patient is a classic hallmark of **Indeterminate Leprosy**. 1. **Why Indeterminate Leprosy is correct:** This is the earliest clinical stage of leprosy. It typically presents as a single, ill-defined, hypopigmented macule. The crucial diagnostic feature is the **impairment of sensation** (temperature or touch) and/or decreased sweating within the patch, caused by early nerve involvement. In children, the face is a common site. Histopathology usually shows a non-specific lymphocytic infiltration around nerves and appendages. 2. **Why other options are incorrect:** * **Lepromatous Leprosy (LL):** This is the multibacillary, polar end of the spectrum. It presents with multiple, symmetrical, shiny nodules or plaques and widespread infiltration (Leonine facies). Sensation is usually preserved in early LL lesions. * **Pityriasis Alba:** A common pediatric condition (often associated with atopy) presenting as ill-defined hypopigmented patches with fine scaling. Crucially, there is **no sensory loss**. * **Asbestosis:** This is a restrictive lung disease caused by asbestos fiber inhalation; it has no relevance to hypopigmented skin lesions. **NEET-PG High-Yield Pearls:** * **Cardinal Signs of Leprosy (WHO):** 1. Hypopigmented/reddish patch with definite loss of sensation. 2. Thickened peripheral nerves. 3. Positive skin smear for Acid Fast Bacilli. * **Indeterminate Leprosy** often heals spontaneously or evolves into other types (Tuberculoid or Lepromatous) depending on the host's cell-mediated immunity (CMI). * **Differential for Hypopigmented patches:** If sensation is lost, think Leprosy. If sensation is intact, consider Pityriasis alba, Vitiligo, or Tinea versicolor.

Q: Cutaneous tuberculosis secondary to underlying infected tissue, such as lymph nodes, is called as?

Scrofuloderma. **Explanation:** **Scrofuloderma (Tuberculosis Colliquativa Cutis)** is the correct answer. It represents a **pericontiguous spread** of tuberculosis to the overlying skin from an underlying infected focus, most commonly a **tuberculous lymph node** (especially cervical), but also from infected bones or joints. It typically presents as firm, painless subcutaneous nodules that eventually break down to form ulcers and sinus tracts with a characteristic "watery" or "cheesy" discharge. **Analysis of Incorrect Options:** * **Lupus Vulgaris:** This is the most common chronic form of cutaneous TB in adults. It occurs via hematogenous, lymphatic, or contiguous spread in individuals with high immunity. The hallmark clinical sign is the **"Apple-jelly nodule"** seen on diascopy. * **Spina Ventosa:** This refers to **tuberculous dactylitis**, involving the short bones of the hands or feet. While it can lead to scrofuloderma of the overlying skin, the term itself refers to the bone pathology, not the cutaneous manifestation. * **Tuberculous Verrucosa Cutis (TVC):** Also known as "Prosector’s wart," this is a form of **exogenous inoculation** TB occurring in previously sensitized individuals with high immunity. It presents as a solitary, warty (verrucous) plaque, usually on the hands. **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** Cutaneous TB is classified based on the bacterial load (**Multibacillary** vs. **Paucibacillary**) and the route of infection. * **Paucibacillary forms:** Lupus Vulgaris, TVC, and Tuberculids. * **Multibacillary forms:** Scrofuloderma, Orificial TB, and Miliary TB. * **Most common type in India:** Lupus Vulgaris (overall), though Scrofuloderma is very common in children.

Q: Which of the following diseases is associated with Erythema migrans?

Lyme's disease. **Explanation:** **Lyme’s Disease (Correct Answer):** Erythema migrans (EM) is the pathognomonic clinical sign of early localized Lyme disease, caused by the spirochete *Borrelia burgdorferi* and transmitted by the *Ixodes* tick. It typically appears 3 to 30 days after a tick bite as an expanding red patch that often clears centrally, creating a classic **"bull’s-eye"** or targetoid appearance. **Analysis of Incorrect Options:** * **Endemic Typhus:** Caused by *Rickettsia typhi* (transmitted by rat fleas). It typically presents with a maculopapular rash starting on the trunk and spreading peripherally, but does not feature erythema migrans. * **Scrub Typhus:** Caused by *Orientia tsutsugamushi*. Its hallmark cutaneous finding is an **eschar** (a necrotic sore with a black crust) at the site of the chigger bite, accompanied by lymphadenopathy. * **Master’s Disease:** Also known as Southern Tick-Associated Rash Illness (STARI). While it produces a rash nearly identical to erythema migrans, it is associated with the *Amblyomma americanum* (Lone Star tick) and is etiologically distinct from Lyme disease. In the context of standard medical examinations, EM is most classically linked to Lyme disease. **NEET-PG High-Yield Pearls:** * **Vector:** *Ixodes* tick (also transmits Babesiosis and Anaplasmosis). * **Stages of Lyme:** 1. Early Localized (Erythema migrans). 2. Early Disseminated (Multiple EM lesions, Bell’s palsy, AV block). 3. Late (Chronic arthritis, Acrodermatitis chronica atrophicans). * **Treatment of Choice:** Doxycycline (Amoxicillin in children <8 years or pregnant women). * **Important Distinction:** Do not confuse the "target lesions" of Erythema Multiforme (associated with HSV) with the "bull's-eye" of Erythema Migrans.

Q: Which of the following is NOT a characteristic of secondary syphilis?

Painful and itchy maculopapular lesions. Syphilis, caused by the spirochete *Treponema pallidum*, is a multi-stage systemic infection. Understanding the clinical presentation of each stage is crucial for NEET-PG. **Why Option B is the Correct Answer:** The hallmark of secondary syphilis is a generalized **non-pruritic (not itchy)** and **painless** maculopapular rash [1]. The rash characteristically involves the **palms and soles**, a high-yield clinical sign [1]. Because the question asks for the "NOT" characteristic, Option B is correct because syphilitic lesions are typically asymptomatic [1]. **Analysis of Incorrect Options:** * **Option A:** Secondary syphilis typically manifests **6 to 8 weeks** (range 2–12 weeks) after the appearance of the primary chancre. In some cases, the chancre may still be healing when the secondary stage begins. * **Option C:** Unlike the primary stage, secondary syphilis is a systemic illness. Patients frequently present with **constitutional symptoms** such as malaise, fever, sore throat, weight loss, and generalized lymphadenopathy (especially epitrochlear nodes). * **Option D:** This stage represents hematogenous dissemination. While rare, it can lead to **organ-specific complications** including aseptic meningitis, hepatitis (with disproportionately high alkaline phosphatase), immune-complex glomerulonephritis (nephrotic syndrome), and ocular involvement like uveitis. **Clinical Pearls for NEET-PG:** * **Condyloma Lata:** Highly infectious, moist, wart-like papules found in intertriginous areas (e.g., axilla, perineum) during the secondary stage [1]. * **Lues Maligna:** A severe, pleomorphic form of secondary syphilis with necrotic lesions, usually seen in HIV-positive patients. * **Diagnosis:** Non-specific treponemal tests (VDRL/RPR) have their highest titers during the secondary stage. If the titer is extremely high, a "Prozone phenomenon" may cause a false negative.

Q: Hutchinson's triad is seen in which of the following conditions?

Congenital syphilis. **Explanation:** **Hutchinson’s Triad** is a classic clinical diagnostic marker for **Late Congenital Syphilis** (presenting after 2 years of age). It occurs due to the systemic inflammatory response to *Treponema pallidum* during fetal development and early childhood. The triad consists of: 1. **Hutchinson’s Teeth:** Notched, peg-shaped permanent upper central incisors. 2. **Interstitial Keratitis:** Chronic inflammation of the corneal stroma leading to corneal scarring and potential blindness (usually appears between ages 5–15). 3. **Sensorineural Hearing Loss:** Caused by eighth cranial nerve (vestibulocochlear) involvement. **Analysis of Options:** * **Option B (Correct):** Congenital syphilis is the only condition where this developmental triad occurs. It is divided into Early (birth to 2 years) and Late (>2 years) stages. * **Option A, C, & D (Incorrect):** Acquired syphilis (Primary, Secondary, and Tertiary) occurs after birth via sexual contact or inoculation. While these stages can involve the eyes (uveitis) or ears (otosyphilis), they do not cause the specific developmental dental deformities or the classic triad seen in the congenital form. **High-Yield Clinical Pearls for NEET-PG:** * **Mulberry Molars:** Another dental sign of congenital syphilis characterized by multiple rudimentary cusps on the first permanent molars. * **Other Late Signs:** Saddle nose deformity, Sabre shins (anterior bowing of the tibia), and Clutton’s joints (painless symmetrical knee swelling). * **Early Signs:** Snuffles (syphilitic rhinitis), pemphigus syphiliticus (bullous lesions), and hepatosplenomegaly. * **Screening:** VDRL/RPR are used for screening; FTA-ABS is the confirmatory treponemal test.

Q: In which stage of syphilis does seropositivity typically become evident?

Muco patches (secondary syphilis). ### Explanation **Correct Answer: B. Muco patches (secondary syphilis)** **Medical Concept:** Seropositivity in syphilis refers to the detection of antibodies via non-treponemal (VDRL, RPR) or treponemal (FTA-ABS, TPHA) tests. In **Primary Syphilis**, the immune system has just been exposed to *Treponema pallidum*; therefore, tests are often negative during the first 1–3 weeks of the chancre's appearance (the "seronegative primary" phase) [1]. By the time the disease progresses to **Secondary Syphilis** (characterized by mucous patches, condyloma lata, and maculopapular rashes), the bacterial load is at its peak and the antibody response is fully developed [1]. Consequently, **seropositivity is 100%** in the secondary stage. **Analysis of Incorrect Options:** * **A. Chancre (Primary Syphilis):** Only about 30–50% of patients are seropositive when the chancre first appears. Diagnosis at this stage relies primarily on **Dark Ground Microscopy (DGM)** to visualize spirochetes. * **C. Gumma (Tertiary Syphilis):** While patients are seropositive here, this is a late manifestation occurring years after infection. The question asks when it *typically becomes evident*, which occurs much earlier in the secondary stage. * **D. Congenital Syphilis:** This is a mode of transmission (vertical) rather than a chronological stage of the primary infection sequence in an adult. **NEET-PG High-Yield Pearls:** * **Gold Standard for Primary Syphilis:** Dark Ground Microscopy (DGM). * **Secondary Syphilis:** Known as the "Great Imitator" and represents the most infectious stage [1]. * **Prozone Phenomenon:** Can cause a false-negative VDRL in secondary syphilis due to excessively high antibody titers; requires serum dilution for diagnosis [1]. * **Specific Test of Choice:** FTA-ABS is usually the first serological test to become positive (earlier than VDRL).

Q: Which of the following stages of syphilis is associated with primary bullous lesions?

Congenital syphilis. **Explanation:** The correct answer is **D. Congenital syphilis**. **Why Congenital Syphilis is Correct:** Syphilis is generally a "non-vesiculobullous" disease in adults. However, **Congenital Syphilis** is a notable exception. It is the only stage where primary bullous lesions, known as **Syphilitic Pemphigus**, occur. These are typically present at birth or appear within the first few weeks of life. The bullae are usually found on the palms and soles, are filled with serous or hemorrhagic fluid, and contain a high concentration of *Treponema pallidum*, making them highly infectious. **Why Other Options are Incorrect:** * **Primary Syphilis:** Characterized by a **Chancre**—a solitary, painless, indurated ulcer with a clean base and regional lymphadenopathy. It does not present with bullae. * **Secondary Syphilis:** Known as the "Great Imitator," it presents with a generalized maculopapular rash (including palms and soles), condyloma lata, and mucous patches. While it can be polymorphic, it **never** presents with vesicles or bullae in adults. * **Tertiary Syphilis:** Characterized by **Gummas** (chronic granulomatous lesions) and cardiovascular or neurological involvement. Bullous lesions are not a feature. **High-Yield Clinical Pearls for NEET-PG:** * **Syphilitic Pemphigus:** Always suspect congenital syphilis if a neonate presents with bullae on the palms and soles. * **Hutchinson’s Triad (Late Congenital Syphilis):** Interstitial keratitis, Hutchinson teeth (notched incisors), and Eighth nerve deafness. * **Drug of Choice:** Parenteral **Penicillin G** remains the gold standard for all stages of syphilis. * **Screening vs. Confirmatory:** VDRL/RPR are used for screening and monitoring treatment response, while TPHA/FTA-ABS are specific treponemal tests used for confirmation.

Q: A 35-year-old male presents with a painless indurated ulcer on the penis and enlarged, non-tender genital lymph nodes. What is the most likely diagnosis?

Syphilis. **Explanation:** The clinical presentation of a **painless, indurated ulcer** (Hard Chancre) associated with **non-tender, rubbery lymphadenopathy** is the classic hallmark of **Primary Syphilis** [1], caused by *Treponema pallidum*. **1. Why Syphilis is correct:** The primary chancre typically appears 3 weeks after exposure. Its defining features are its lack of pain and "button-like" induration (firmness). The associated inguinal lymphadenopathy is characteristically bilateral, painless, and non-suppurative, which matches the patient's description perfectly [1]. **2. Why other options are incorrect:** * **Chancroid (*Haemophilus ducreyi*):** Presents as a **painful**, soft ulcer with a ragged edge. The associated lymphadenopathy (bubo) is very painful and often undergoes suppuration [2]. * **Herpes Genitalis (HSV-2):** Presents as multiple, small, **painful vesicles** on an erythematous base that rupture to form shallow ulcers [1]. It is not indurated. * **Lymphogranuloma Venereum (LGV):** The initial primary lesion is a transient, painless papule or ulcer that often heals unnoticed. The dominant clinical feature is painful, massive inguinal lymphadenopathy (the "Groove sign") [2]. **Clinical Pearls for NEET-PG:** * **Investigation of choice:** Dark-field microscopy (to see corkscrew motility) is used for early lesions; VDRL/RPR are used for screening (but may be negative in the first 1-2 weeks of the chancre). * **Treatment:** Benzathine Penicillin G (2.4 million units IM single dose) remains the gold standard. * **Induration:** If an ulcer is firm/hard, think Syphilis; if it is soft/friable, think Chancroid.

Question 1

Lucio reaction is seen in which of the following conditions?

Accepted Answer

Leprosy

Answer

Tuberculosis

Answer

Syphilis

Answer

Lymphogranuloma venereum

Question 2

The primary lesion of syphilis, the Hunterian chancre, is characterized by which of the following features, EXCEPT?

Accepted Answer

Bleeding

Answer

Painless

Answer

Indurated

Answer

Shallow ulcer

Question 3

A 12-year-old boy presents with a white facial lesion that has grown noticeably large. Examination reveals hypoesthesia over the lesion and a smooth surface. What is the likely diagnosis?

Accepted Answer

Indeterminate leprosy

Answer

Lepromatous leprosy

Answer

Pityriasis alba

Answer

Asbestosis

Question 4

Cutaneous tuberculosis secondary to underlying infected tissue, such as lymph nodes, is called as?

Accepted Answer

Scrofuloderma

Answer

Lupus Vulgaris

Answer

Spina Ventosa

Answer

Tuberculous Verrucosa Cutis

Question 5

Which of the following diseases is associated with Erythema migrans?

Accepted Answer

Lyme's disease

Answer

Endemic typhus

Answer

Scrub typhus

Answer

Master's disease

Question 6

Which of the following is NOT a characteristic of secondary syphilis?

Accepted Answer

Painful and itchy maculopapular lesions

Answer

Occurs 6-8 weeks after the development of the chancre

Answer

Constitutional features are present

Answer

Meningitis, hepatitis, glomerulonephritis, and uveitis may occur

Question 7

Hutchinson's triad is seen in which of the following conditions?

Accepted Answer

Congenital syphilis

Answer

Primary syphilis

Answer

Secondary syphilis

Answer

Tertiary syphilis

Question 8

In which stage of syphilis does seropositivity typically become evident?

Accepted Answer

Muco patches (secondary syphilis)

Answer

Chancre (primary syphilis)

Answer

Gum ma (tertiary syphilis)

Answer

Congenital syphilis

Question 9

Which of the following stages of syphilis is associated with primary bullous lesions?

Accepted Answer

Congenital syphilis

Answer

Primary syphilis

Answer

Secondary syphilis

Answer

Tertiary syphilis

Question 10

A 35-year-old male presents with a painless indurated ulcer on the penis and enlarged, non-tender genital lymph nodes. What is the most likely diagnosis?

Accepted Answer

Syphilis

Answer

Chancroid

Answer

Herpes genitalis

Answer

Lymphogranuloma venereum (LGV)

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

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