Bacterial Skin Infections Practice Questions

Q: A saucer-shaped lesion is found in which type of leprosy?

Borderline leprosy. **Explanation:** The **saucer-shaped lesion** (also known as the "inverted saucer" appearance) is a classic morphological hallmark of **Borderline Tuberculoid (BT)** or **Borderline Borderline (BB)** leprosy. This appearance is characterized by a lesion with a well-defined, raised, and erythematous outer edge that slopes gradually toward a flattened, pale, or hypopigmented center. **Why Borderline Leprosy is correct:** In the Ridley-Jopling classification, borderline cases represent an unstable immunological state. The "saucer" morphology occurs because the body attempts to contain the infection (leading to the raised, active border) but fails to do so completely, resulting in a large, asymmetrical lesion with central clearing or flattening. **Analysis of Incorrect Options:** * **Lepromatous Leprosy (LL):** Presents with multiple, symmetrical, small macules, papules, or nodules (lepromas). The lesions have vague borders and do not show the characteristic saucer shape. * **Tuberculoid Leprosy (TT):** Typically presents as a single (or very few), well-defined, anesthetic, hairless plaque. While the margins are sharp, they do not typically exhibit the specific "sloping" saucer morphology seen in borderline types. * **Indeterminate Leprosy:** This is the earliest stage, presenting as a single, ill-defined hypopigmented macule with vague borders and no significant sensory loss. **High-Yield Clinical Pearls for NEET-PG:** * **Swiss-Cheese Appearance:** Characteristic of **Borderline Borderline (BB)** leprosy, where "punched-out" clear areas appear within a large plaque. * **Leonine Facies:** Seen in **Lepromatous Leprosy (LL)** due to diffuse infiltration of the face. * **Nerve Involvement:** Nerve thickening is most asymmetrical in BT leprosy but most extensive/symmetrical in LL. * **Madarosis:** Loss of the lateral one-third of eyebrows, a classic sign of LL.

Q: The Buschke-Ollendroff sign is seen in which stage of syphilis?

Secondary syphilis. **Explanation:** The **Buschke-Ollendorff sign** (also known as the "probe sign") is a classic clinical finding in **Secondary Syphilis**. It refers to the elicitation of exquisite, deep-seated tenderness when a papular syphilitic lesion (syphilid) is pressed with a blunt probe or a pinhead. This occurs because the inflammatory infiltrate in secondary syphilis is often dense and located deep within the dermis, putting pressure on local nerve endings. **Analysis of Options:** * **Secondary Syphilis (Correct):** This stage is the "Great Imitator," characterized by generalized lymphadenopathy and polymorphic skin eruptions. The Buschke-Ollendorff sign is specifically associated with the papular lesions of this stage. * **Primary Syphilis:** Characterized by the **Chancre** (a painless, indurated ulcer). Since the hallmark of primary syphilis is painlessness, this sign is absent. * **Tertiary Syphilis:** Characterized by **Gummas** (granulomatous nodules) or cardiovascular/neurosyphilis. While gummas can be destructive, they do not typically exhibit this specific probe tenderness. * **Congenital Syphilis:** Presents with features like snuffles, Hutchinson’s triad, or Mulberry molars, but the Buschke-Ollendorff sign is not a diagnostic feature here. **High-Yield Clinical Pearls for NEET-PG:** * **Ollendorff’s Sign vs. Buschke-Ollendorff Syndrome:** Do not confuse this sign with *Buschke-Ollendorff Syndrome*, which is a genetic connective tissue disorder characterized by dermatofibrosis lenticularis disseminata and osteopoikilosis. * **Other signs in Secondary Syphilis:** Look for **Biett’s Collarette** (a ring of scales around papules) and **Condyloma Lata** (highly infectious moist papules in intertriginous areas). * **Palm/Sole involvement:** Secondary syphilis is a top differential for any maculopapular rash involving the palms and soles.

Q: Which peripheral nerve is most commonly affected in leprosy?

Ulnar. **Explanation:** Leprosy (*Hansen’s Disease*), caused by *Mycobacterium leprae*, is a chronic infectious disease that primarily targets the skin and peripheral nerves [1]. The bacilli have a predilection for cooler areas of the body, which explains why superficial nerve trunks are most affected. **1. Why Ulnar Nerve is Correct:** The **Ulnar nerve** is the most commonly involved peripheral nerve in leprosy. It is typically affected just proximal to the cubital tunnel at the elbow. The resulting inflammation (neuritis) leads to nerve thickening, loss of sensation in the ulnar distribution, and characteristic motor weakness leading to a **"Claw Hand"** deformity (specifically involving the ring and little fingers). **2. Analysis of Incorrect Options:** * **Radial Nerve:** While it can be involved (leading to wrist drop), it is less common than the ulnar or median nerves. * **Median Nerve:** This is the second most common nerve affected in the upper limb. Involvement at the wrist leads to "Ape Thumb" deformity. * **Popliteal Nerve:** This is a general term; specifically, the **Common Peroneal nerve** (a branch of the sciatic nerve) is the most common nerve affected in the **lower limb**, leading to foot drop. However, globally, the ulnar nerve remains the most frequent overall. **3. Clinical Pearls for NEET-PG:** * **Most common nerve involved overall:** Ulnar nerve. * **Most common nerve in the lower limb:** Common Peroneal nerve. * **Most common cranial nerve involved:** Facial nerve (CN VII), leading to lagophthalmos. * **Cardinal Sign:** Thickened, palpable nerves are a diagnostic hallmark of leprosy [1]. * **Deformity:** The "Claw Hand" in leprosy is often a "Total Claw Hand" if both Ulnar and Median nerves are involved.

Q: Manifestations of erythema nodosum leprosum (ENL) include all of the following except:

Pancreatitis. **Explanation:** **Erythema Nodosum Leprosum (ENL)**, also known as a **Type 2 Lepra Reaction**, is a systemic immune-complex-mediated (Type III hypersensitivity) reaction occurring primarily in patients with lepromatous (LL) or borderline lepromatous (BL) leprosy. It is characterized by the deposition of immune complexes in various tissues, leading to widespread inflammatory manifestations. 1. **Why Pancreatitis is the correct answer:** While ENL is a multisystem disorder, **pancreatitis is not a recognized manifestation**. The inflammation typically targets the skin, nerves, eyes, joints, and certain internal organs like the liver, kidneys, and testes. Pancreatitis is not part of the clinical spectrum of Type 2 reactions. 2. **Analysis of incorrect options:** * **Fever:** ENL is a systemic illness. High-grade fever, malaise, and constitutional symptoms are hallmark features of the reaction. * **Hepatitis:** The immune complex deposition can involve internal organs. Hepatosplenomegaly and transient hepatitis (elevated liver enzymes) are documented systemic features of severe ENL. 3. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Tender, evanescent (short-lived) erythematous nodules + Fever + Systemic involvement. * **Common Sites:** Extensor surfaces of limbs and the face. * **Other Systemic Features:** Iridocyclitis (eye), Orchitis (testes—can lead to sterility), Glomerulonephritis (kidney), Arthritis, and Lymphadenopathy. * **Drug of Choice:** **Thalidomide** is the most effective treatment for severe ENL. Prednisolone and Clofazimine are also used. * **Trigger:** Often triggered by the initiation of MDT (due to rapid antigen release), pregnancy, or stress.

Q: Tender buboes are used in the diagnosis of which condition?

Chancroid. **Chancroid** is caused by the Gram-negative coccobacillus *Haemophilus ducreyi*. The clinical hallmark of this condition is the presence of **painful (tender) genital ulcers** [1] accompanied by **painful, fluctuant inguinal lymphadenopathy**, known as **buboes** [1]. These buboes are typically unilateral and, if left untreated, may undergo spontaneous rupture, leading to chronic draining sinuses. **Analysis of Options:** * **Gonorrhoea:** Primarily presents as urethritis (purulent discharge) or cervicitis. While it can cause pelvic inflammatory disease, it does not typically present with tender inguinal buboes. * **Herpes (HSV-2):** Presents with multiple, small, grouped vesicles on an erythematous base that rupture to form shallow, painful ulcers. While lymphadenopathy may be present, it is usually bilateral and non-suppurative, unlike the classic bubo of Chancroid. * **Granuloma venereum (Donovanosis):** Caused by *Klebsiella granulomatis*. It is characterized by **painless**, beefy-red, velvety ulcers [1]. A key feature is "pseudobuboes"—which are subcutaneous nodules rather than true lymphadenopathy. **NEET-PG High-Yield Pearls:** * **The "Pain" Rule:** Chancroid and Herpes are **Painful**; Syphilis and Lymphogranuloma Venereum (LGV) are generally **Painless** (though LGV buboes can become painful later). * **School of Fish Appearance:** Classic Gram stain finding for *H. ducreyi*. * **LGV vs. Chancroid:** Both cause buboes, but LGV (Chlamydia L1-L3) features the **"Groove Sign"** (Poupart’s ligament dividing the nodes) and the initial ulcer is usually evanescent (disappears quickly). * **Treatment of Chancroid:** Single dose of Azithromycin (1g) or Ceftriaxone (250mg IM).

Q: A 45-year-old lorry driver from Bihar presented with multiple painful, necrotic ulcers on the penis and tender inguinal lymphadenopathy. What is the diagnosis?

Haemophilus ducreyi. **Explanation:** The clinical presentation of **painful, necrotic ulcers** associated with **tender inguinal lymphadenopathy** (buboes) is the classic hallmark of **Chancroid**, caused by the Gram-negative coccobacillus ***Haemophilus ducreyi*** [2]. **1. Why Option A is Correct:** * **Painful Ulcers:** Unlike syphilis, chancroid presents with extremely painful, "soft" ulcers with ragged, undermined edges and a necrotic/purulent base [2]. * **Bubo Formation:** Inguinal lymphadenopathy in chancroid is typically unilateral, very painful, and prone to suppuration (forming a bubo) [2]. * **Demographics:** Lorry drivers are a high-risk group frequently cited in NEET-PG vignettes for Sexually Transmitted Infections (STIs). **2. Why Other Options are Incorrect:** * **B. Herpes Simplex Virus (HSV):** While painful, HSV presents as multiple small, superficial vesicles on an erythematous base that rupture to form shallow ulcers [1]. It lacks the deep, necrotic character of chancroid. * **C. Syphilis (*Treponema pallidum*):** The primary chancre of syphilis is characteristically **painless**, indurated ("hard"), and clean-based, with painless regional lymphadenopathy [1]. * **D. Chlamydia trachomatis (LGV):** Lymphogranuloma Venereum (serovars L1-L3) typically presents with a transient, painless primary papule/ulcer that heals quickly, followed later by painful "Groove sign" lymphadenopathy [2]. **Clinical Pearls for NEET-PG:** * **School of Fish Appearance:** Classic microscopic finding of *H. ducreyi* on Gram stain (parallel chains). * **Railroad Track Appearance:** Another descriptive term for the arrangement of the bacilli. * **Treatment:** A single dose of **Azithromycin (1g)** or Ceftriaxone (250mg IM). * **Mnemonic:** "Ducreyi makes you **cry**" (because it is painful).

Q: What is considered successful treatment of chancroid?

Objective improvement occurs within 1 week.. Chancroid, caused by the Gram-negative coccobacillus *Haemophilus ducreyi*, is characterized by painful genital ulcers and associated regional lymphadenopathy (buboes). **1. Why Option B is Correct:** According to standard clinical guidelines (including CDC and WHO), successful treatment of chancroid is defined by **objective clinical improvement**—meaning the ulcer shows visible signs of healing (re-epithelialization or decreased size)—within **3 to 7 days (1 week)** after starting effective antibiotic therapy. While pain may improve sooner, the physical resolution of the lesion is the clinical benchmark for success. **2. Why Other Options are Incorrect:** * **Options A & C:** "Symptomatic improvement" refers primarily to the reduction of pain. While pain relief usually occurs within 48–72 hours, it is subjective. Objective physical improvement is the standard metric for confirming treatment efficacy. * **Option D:** A 2-week window is too long for an initial assessment. If no objective improvement is noted within 7 days, clinicians must re-evaluate for a wrong diagnosis, co-infection (e.g., HSV or Syphilis), or antimicrobial resistance. **High-Yield Clinical Pearls for NEET-PG:** * **The "3 Ps" of Chancroid:** **P**ainful, **P**urulent, and **P**unched-out ulcer. * **Microscopy:** "School of fish" or "Railroad track" appearance on Gram stain. * **Treatment of Choice:** Azithromycin (1g orally, single dose) or Ceftriaxone (250mg IM, single dose). * **Bubo Management:** Large, fluctuant buboes should be managed with **needle aspiration**, not incision and drainage, to prevent the formation of chronic draining sinuses. * **Healing Time:** While improvement starts within 1 week, complete healing of large ulcers may take >2 weeks.

Q: What is the most likely diagnosis for a patient presenting with a painful ulcer on the glans penis?

Chancroid. The diagnosis of genital ulcers is a high-yield topic for NEET-PG, primarily differentiated by the presence or absence of pain and the characteristics of the lesion. [1] ### **Why Chancroid is Correct** **Chancroid**, caused by the gram-negative coccobacillus *Haemophilus ducreyi*, is classically characterized by a **painful**, "soft" ulcer. [1] The pain is the hallmark clinical feature that distinguishes it from many other STIs. These ulcers often have ragged, undermined edges and a necrotic base (grayish-yellow exudate). They are frequently associated with painful, inflammatory inguinal lymphadenopathy (buboes) which may suppurate. ### **Why Other Options are Incorrect** * **Syphilis (Option A):** Primary syphilis presents as a **painless**, indurated (hard) ulcer with a clean base. [1] * **Chancre (Option D):** This is the clinical term for the primary lesion of syphilis. By definition, a classic chancre is **painless**. * **Lymphogranuloma Venereum (LGV) (Option B):** Caused by *Chlamydia trachomatis* (L1-L3), the primary lesion is a small, transient, **painless** papule or ulcer that often heals unnoticed before the painful "groove sign" (lymphadenopathy) develops. [1] ### **NEET-PG High-Yield Pearls** * **Mnemonic for Pain:** "You **do cry** (*H. ducreyi*) because it's **painful** (Chancroid)." * **School of Fish Appearance:** On Gram stain, *H. ducreyi* shows a characteristic "railroad track" or "school of fish" pattern. * **Donovanosis (Granuloma Inguinale):** Another differential; presents as beefy-red, **painless** ulcers that bleed on touch (pseudo-buboes). [1] Look for "Donovan bodies" (safety-pin appearance) on biopsy. * **Treatment of Chancroid:** Azithromycin (1g orally) or Ceftriaxone (250mg IM).

Q: A 23-year-old presented with a painless penile ulcer and painless lymphadenopathy. What is the diagnosis?

Syphilis. The clinical presentation of a **painless penile ulcer** (chancre) associated with **painless regional lymphadenopathy** is the classic hallmark of **Primary Syphilis**, caused by the spirochete *Treponema pallidum*. ### Why Syphilis is Correct: The primary chancre typically appears 3 weeks after exposure. It is characterized by a clean base, indurated (hard) edges, and a lack of exudate. Crucially, both the ulcer and the associated inguinal lymphadenopathy are **painless**, which distinguishes it from most other genital ulcerative diseases. ### Why Other Options are Incorrect: * **Chancroid (*Haemophilus ducreyi*):** Presents as a **painful** ulcer with a ragged, undermined edge and a necrotic base. The associated lymphadenopathy (bubo) is also exquisitely painful and may suppurate. * **Donovanosis (Granuloma Inguinale):** Caused by *Klebsiella granulomatis*. It presents as chronic, beefy-red, painless ulcers that bleed on touch. Notably, there is **no true lymphadenopathy**, though "pseudo-buboes" (subcutaneous granulation) may occur. * **Herpes (HSV-2):** Presents as multiple, small, **painful** vesicles that rupture to form shallow ulcers. It is often associated with systemic symptoms like fever and painful lymphadenopathy. ### High-Yield Clinical Pearls for NEET-PG: * **Hard Chancre:** Syphilis (Indurated). * **Soft Chancre:** Chancroid (Non-indurated). * **Diagnosis:** Dark-ground microscopy is the gold standard for primary syphilis (shows corkscrew motility). VDRL/RPR are screening tests but may be negative in the very early stages. * **Treatment:** Benzathine Penicillin G (2.4 million units IM) is the drug of choice.

Q: Which of the following is NOT involved in leprosy?

Central Nervous System (CNS). **Explanation:** The correct answer is **A. Central Nervous System (CNS)**. **Why CNS is not involved:** *Mycobacterium leprae* has a unique predilection for cooler areas of the body. The organism thrives at temperatures between **30°C and 33°C**. The Central Nervous System (brain and spinal cord) is protected by the blood-brain barrier and maintains a core body temperature of approximately **37°C**, which is inhibitory to the growth and survival of *M. leprae*. Therefore, leprosy characteristically spares the CNS. **Why the other options are involved:** * **Skin (C):** This is the most common site of involvement [1]. Lesions range from hypopigmented patches in Tuberculoid leprosy to diffuse infiltration and nodules (lepromas) in Lepromatous leprosy. * **Testis (B):** The testes are located outside the body cavity to maintain a lower temperature, making them a prime target. Involvement can lead to orchitis, testicular atrophy, and subsequent sterility or gynecomastia [1]. * **Cornea (D):** The anterior segment of the eye is cooler than the posterior segment. Leprosy frequently affects the cornea (keratitis), iris, and ciliary body, potentially leading to blindness [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Target Tissues:** *M. leprae* primarily affects the skin, peripheral nerves (especially the ulnar, common peroneal, and posterior tibial), anterior chamber of the eye, upper respiratory tract mucosa, and testes [1]. * **Nerve Involvement:** It is the most common cause of peripheral neuropathy worldwide. * **Immune Response:** The clinical spectrum depends on the host’s **Cell-Mediated Immunity (CMI)**; strong CMI leads to Tuberculoid (TT), while weak CMI leads to Lepromatous (LL) leprosy [1]. * **Cardinal Signs:** Hypopigmented patches with loss of sensation, thickened peripheral nerves, and a positive slit-skin smear [1].

Question 1

A saucer-shaped lesion is found in which type of leprosy?

Accepted Answer

Borderline leprosy

Answer

Lepromatous leprosy

Answer

Tuberculoid leprosy

Answer

Indeterminate leprosy

Question 2

The Buschke-Ollendroff sign is seen in which stage of syphilis?

Accepted Answer

Secondary syphilis

Answer

Primary syphilis

Answer

Congenital syphilis

Answer

Tertiary syphilis

Question 3

Which peripheral nerve is most commonly affected in leprosy?

Accepted Answer

Ulnar

Answer

Radial

Answer

Median

Answer

Popliteal

Question 4

Manifestations of erythema nodosum leprosum (ENL) include all of the following except:

Accepted Answer

Pancreatitis

Answer

Fever

Answer

Hepatitis

Answer

All of the above

Question 5

Tender buboes are used in the diagnosis of which condition?

Accepted Answer

Chancroid

Answer

Gonorrhoea

Answer

Herpes

Answer

Granuloma venereum

Question 6

A 45-year-old lorry driver from Bihar presented with multiple painful, necrotic ulcers on the penis and tender inguinal lymphadenopathy. What is the diagnosis?

Accepted Answer

Haemophilus ducreyi

Answer

Herpes simplex virus

Answer

Syphilis

Answer

Chlamydia trachomatis infection

Question 7

What is considered successful treatment of chancroid?

Accepted Answer

Objective improvement occurs within 1 week.

Answer

Symptomatic improvement occurs within 1 week.

Answer

Symptomatic improvement occurs within 2 weeks.

Answer

Objective improvement occurs within 2 weeks.

Question 8

What is the most likely diagnosis for a patient presenting with a painful ulcer on the glans penis?

Accepted Answer

Chancroid

Answer

Syphilis

Answer

Lymphogranuloma venerum

Answer

Chancre

Question 9

A 23-year-old presented with a painless penile ulcer and painless lymphadenopathy. What is the diagnosis?

Accepted Answer

Syphilis

Answer

Chancroid

Answer

Donovanosis

Answer

Herpes

Question 10

Which of the following is NOT involved in leprosy?

Accepted Answer

Central Nervous System (CNS)

Answer

Testis

Answer

Skin

Answer

Cornea

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

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