Bacterial Skin Infections Practice Questions

Q: A 30-year-old female presents with a painful red granular lesion on the vulva accompanied by bilateral lymphadenopathy. What is the most likely diagnosis?

Chancroid. ***Chancroid***- Caused by ***Haemophilus ducreyi***, it presents classically as a **painful, ragged, deep vulvar ulcer** (soft chancre) often described as having an erythematous or granular base.- The condition is characteristically associated with large, sometimes suppurative, **painful unilateral or bilateral inguinal lymphadenopathy** (**buboes**), which fits the combined clinical presentation of pain and lymphadenopathy.*Neisseria Gonorrhoeae Infection*- This infection primarily causes **mucopurulent urethritis** or **cervicitis** and is not typically associated with primary, ulcerative, or granular vulval lesions.- While regional lymphadenopathy may occur, it is usually not a prominent, painful finding defining the clinical presentation.*Granuloma Inguinale*- The characteristic lesion is a **painless, highly vascular, 'beefy red' ulcer** which bleeds easily, consistent with the term "granular" but contradicting the crucial feature of being **painful**.- True regional lymphadenopathy is rare; instead, subcutaneous granulomas may mimic lymph nodes (**pseudo-buboes**).*Lymphogranuloma Venereum*- The primary genital lesion is typically a small, **painless, transient papule** or vesicle that is often overlooked.- While it causes severe, painful inguinal lymphadenopathy, the initial vulval lesion is usually not a prominent, painful, granular ulcer as described.

Q: A person with the H/o long-term sexual relationship presented with painful ulcers on his genitals with tender lymphadenopathy. What is the diagnosis?

Chancroid. ***Chancroid*** - Caused by the bacterium **_Haemophilus ducreyi_**, it classically presents with one or more deep, painful genital ulcers that have ragged, undermined borders and a purulent base. - It is characteristically associated with tender, suppurative inguinal lymphadenopathy, often unilateral, which is consistent with the patient's presentation. *Gonorrhoea* - Caused by **_Neisseria gonorrhoeae_**, it typically presents as **purulent urethritis** or cervicitis with discharge and dysuria. - While it can cause systemic infection, painful genital ulcers are not a characteristic feature of a primary gonococcal infection. *Chlamydia* - Caused by **_Chlamydia trachomatis_** (serovars D-K), it is a leading cause of nongonococcal urethritis and is frequently asymptomatic, especially in women. - This infection does not typically cause painful genital ulcers; its presentation is more commonly urethritis, cervicitis, or pelvic inflammatory disease. *LGV* - Lymphogranuloma venereum (LGV) is caused by invasive serovars (L1, L2, L3) of **_Chlamydia trachomatis_**. - It typically begins with a small, transient, **painless** papule or ulcer, followed by the development of painful inguinal lymphadenopathy (buboes), which differentiates it from the painful ulcers of chancroid.

Q: A 45-year-old truck driver with a history of multiple sex partners presented to the dermatological department, as shown below. What is the likely diagnosis?

Secondary syphilis. ***Secondary syphilis*** - The image shows a classic **maculopapular rash** involving the **palms**, a hallmark feature of secondary syphilis, which is caused by the spirochete **Treponema pallidum**. - The patient's history of **multiple sex partners** is a significant risk factor, and other associated findings can include generalized lymphadenopathy, fever, and **condylomata lata**. *Lichen planus* - Characterized by the "6 P's": **pruritic, polygonal, planar, purple papules and plaques**, often with fine white lines on the surface known as **Wickham's striae**. - The lesions in the image lack these classic features and are not typically pruritic, distinguishing it from the presented case. *Scabies* - This is an intensely **pruritic** infestation caused by the mite **Sarcoptes scabiei**, which creates linear **burrows**, especially in the **interdigital web spaces**, wrists, and axillae. - The rash in secondary syphilis is classically non-pruritic, and the morphology is maculopapular rather than burrow-like. *Psoriasis* - Typically presents as **well-demarcated erythematous plaques** with a **silvery scale** on extensor surfaces like the elbows and knees. - While palmoplantar psoriasis occurs, it usually manifests as hyperkeratotic plaques or pustules, not the diffuse maculopapular rash seen here.

Q: A patient presents with erythematous streaks extending peripherally from a site of infection on the skin. Involvement of which of the following structures leads to this clinical presentation?

Superficial lymphatics. ***Superficial lymphatics*** (Assuming the image shows signs of **lymphangitis** or **cellulitis**, characterized by **red streaks** spreading from an infected site.)- The classic presentation of **acute lymphangitis** involves **erythematous streaks** extending peripherally from a site of infection (often a wound or cellulitis), which are typically visible superficial structures.- This pattern suggests inflammation and infection tracking along the **superficial lymphatic vessels** which drain the peripheral skin and subcutaneous tissues.*Deep lymphatics*- Involvement of the **deep lymphatics** (e.g., those alongside major blood vessels) typically leads to **lymphedema** (swelling) of the entire limb, rather than the visible **red streaking** seen in acute superficial lymphangitis.- They are located deeper and their inflammation is less likely to produce the superficial, linear rash visible on the skin.*Superficial veins*- Inflammation and thrombosis of superficial veins (**superficial thrombophlebitis**) typically presents as a localized, **palpable, tender cord** rather than multiple linear streaks that spread over distance, which are characteristic of lymphatic tracing.- This condition would primarily involve blood flow obstruction, not the characteristic infection tracking seen in lymphangitis.*Skin*- Although the signs are *visible* on the skin, the primary pathological process causing the streaks is the infection spreading *within* the **lymphatic vessels** beneath the skin surface, not solely a primary skin disease (like **erysipelas** or **cellulitis** alone).- Cellulitis is often the source, but the visible tracking (streaks) follows the path of the **superficial lymphatics**.

Q: A 45-year-old man with multiple sexual partners presents with a palmoplantar rash as seen below. On examination, he has epitrochlear lymphadenopathy. Which of the following is the likely diagnosis?

Secondary syphilis. ***Secondary syphilis*** - The classic rash of secondary syphilis is a diffuse, maculopapular eruption that characteristically involves the **palms and soles**, as seen in the image. A history of multiple sexual partners is a major risk factor. - **Epitrochlear lymphadenopathy** is a highly suggestive, though not pathognomonic, sign of secondary syphilis. Other systemic symptoms may include fever, malaise, and **condylomata lata**. *Psoriasis* - While psoriasis can affect the palms and soles (**palmoplantar psoriasis**), it typically presents as well-demarcated, erythematous plaques with a silvery scale, which differs from the rash shown. - Psoriasis is an autoimmune condition and is not associated with **epitrochlear lymphadenopathy** or risk factors like multiple sexual partners. *Meningococcemia* - This is an acute, life-threatening infection that presents with a **petechial or purpuric rash** that can become necrotic, not a papular rash on the palms and soles. - Patients with **meningococcemia** are typically systemically unwell with high fever, hypotension, and signs of meningitis, which are absent in this presentation. *Steven Johnson syndrome* - SJS is a severe mucocutaneous reaction characterized by **targetoid lesions**, bullae, and epidermal detachment, which are not features of the rash shown. - A key feature of SJS is severe involvement of at least two **mucous membranes** (e.g., oral, ocular, genital), which is not mentioned in this case.

Q: A patient presents with an indurated plaque on the cheek with central atrophy. Chest X-ray reveals apical calcification. Which of the following tests is most appropriate to confirm the diagnosis?

PCR. ***PCR*** - The clinical picture of an indurated plaque (often exhibiting **apple-jelly nodules** on diascopy) with central atrophy, coupled with radiological evidence of old pulmonary TB (apical calcification), strongly suggests **Lupus Vulgaris** (cutaneous tuberculosis). - **PCR (Polymerase Chain Reaction)** is the most sensitive and specific method for confirming the diagnosis by detecting *Mycobacterium tuberculosis* DNA, which is essential as Lupus Vulgaris is typically a **paucibacillary** condition where AFB staining and culture often fail. *Mantoux test* - The **Mantoux test** assesses delayed-type hypersensitivity (Type IV reaction) to tuberculin antigens and indicates prior exposure to TB or BCG vaccination. - It is useful for screening but **does not confirm active disease** (Lupus Vulgaris) and can be negative in immunocompromised patients or anergic forms. *Slit skin smear* - **Slit skin smear** is the diagnostic method primarily used to detect **acid-fast bacilli** (*M. leprae*) and classify **Leprosy** (Hansen's disease). - It is **not the investigation of choice** for diagnosing tuberculosis. *Probe test* - Nucleic acid **probe tests** (hybridization) are molecular techniques used to identify *M. tuberculosis* but are generally less sensitive than modern **PCR** assays, especially when dealing with limited tissue samples or low bacterial load. - **PCR** is the superior and more widely employed molecular diagnostic standard for confirming paucibacillary TB.

Q: A male presents with lesions as shown in the image and a history of unprotected sexual intercourse a few months ago. What is the most appropriate investigation to confirm the diagnosis?

Serology. ***Serology*** - The clinical presentation (diffuse body rash, often involving the palms and soles, following recent unprotected sexual exposure) is highly suggestive of **Secondary Syphilis**. - **Serological tests** (Non-treponemal tests like RPR/VDRL and specific Treponemal tests like TPPA/FTA-ABS) are the definitive and most appropriate confirmatory investigation for syphilis. *Tzanck smear* - This test is used primarily for the rapid diagnosis of vesicular lesions caused by herpes viruses, such as **Herpes Simplex Virus (HSV)** or **Varicella-Zoster Virus (VZV)**. - It is not indicated for the diagnosis of the typical maculopapular rash seen in secondary syphilis. *KOH* - **Potassium hydroxide (KOH) preparation** is a direct microscopy test specifically used to identify structures like hyphae and spores in the diagnosis of **superficial fungal infections**. - The patient's presentation with a rash secondary to sexually transmitted infection is not typically investigated using KOH. *Biopsy* - While a skin biopsy might confirm the diagnosis histologically (showing characteristic perivascular infiltrate), it is **invasive** and generally reserved for cases where serology is equivocal or the presentation is atypical. - **Serology** provides a systemic assessment and is the standard initial confirmatory test for syphilis.

Q: Best drug for the condition shown below is: (NEET Jan 2018)

Doxycycline. ***Correct: Doxycycline*** - The image shows a **tick embedded in the skin** with surrounding erythema, indicative of a **tick bite** and potential **Lyme disease** or other tick-borne infections. - **Doxycycline** is the **drug of choice** for early Lyme disease (caused by *Borrelia burgdorferi*) and many other common tick-borne illnesses like Rickettsial infections (e.g., Rocky Mountain Spotted Fever) and Anaplasmosis. *Incorrect: Ivermectin* - **Ivermectin** is primarily used to treat **parasitic worm infections** like onchocerciasis, strongyloidiasis, and scabies. - It is **not effective** against bacterial infections transmitted by ticks. *Incorrect: Sulphonamides* - **Sulphonamides** are a class of **antibiotics** effective against various bacterial infections, but they are generally **not the first-line treatment** for tick-borne diseases. - For tick-borne illnesses, **doxycycline** typically has broader and more effective coverage. *Incorrect: Penicillin* - **Penicillin** is an **antibiotic** primarily effective against a range of gram-positive and some gram-negative bacteria, and spirochetes like *Treponema pallidum*. - While it has some activity against *Borrelia burgdorferi* (Lyme disease), **doxycycline is preferred** for early-stage Lyme disease and is specifically active against other common tick-borne pathogens where penicillin is not.

Q: The following lesion is diagnostic of:

Donovanosis. ***Donovanosis*** - The image shows a **granulomatous, beefy-red ulcer** with rolled borders, which is characteristic of **Donovanosis (granuloma inguinale)**. - This condition is caused by *Klebsiella granulomatis* and typically presents as a painless, progressive ulcerative lesion that can bleed easily. *Syphilis* - Syphilitic chancres are typically **painless, indurated ulcers with clean bases** and well-demarcated borders. - They are usually single, appear about 3 weeks after exposure, and are not beefy-red or friable like the lesion shown. *Chancroid* - Chancroid lesions are typically **painful, ragged ulcers with undermined edges** and often have a gray or yellow exudate. - They tend to be multiple and soft, in contrast to the single, granulomatous lesion seen. *Herpes* - Genital herpes presents as **multiple, painful vesicles** that rupture to form shallow ulcers, which then crust over. - The lesions are usually acute, often recurrent, and do not resemble the chronic, proliferative ulceration shown in the image.

Q: A 20-year-old patient presents with urethral discharge. What is the possible diagnosis?

Gonorrhea. ***Gonorrhea*** - The image shows a thick, **purulent urethral discharge**, which is characteristic of **gonococcal urethritis** caused by *Neisseria gonorrhoeae*. - This presentation is consistent with the rapid onset of severe symptoms often seen in gonorrhea. *Chlamydia trachomatis* - While *Chlamydia trachomatis* also causes urethritis, the discharge is typically **less purulent** and more **mucopurulent or watery**, unlike the thick discharge shown. - Chlamydial infections are often **asymptomatic** or cause milder symptoms compared to gonorrhea. *Ureaplasma urealyticum* - *Ureaplasma urealyticum* is a common cause of **non-gonococcal urethritis (NGU)**, but the discharge is usually **scant** and **watery**, not the frank pus seen in the image. - Diagnosis of *Ureaplasma* urethritis typically requires specific laboratory testing, as the clinical presentation is less distinct. *Trichomonas vaginalis* - *Trichomonas vaginalis* can cause urethritis in men, often presenting with **mild or asymptomatic discharge** that can be **clear or mucopurulent**. - A purulent discharge like the one depicted is less typical for *Trichomonas* infection in men; it is more commonly associated with vaginitis in women.

Question 1

A 30-year-old female presents with a painful red granular lesion on the vulva accompanied by bilateral lymphadenopathy. What is the most likely diagnosis?

Accepted Answer

Chancroid

Answer

Neisseria Gonorrhoeae Infection

Answer

Lymphogranuloma Venereum

Answer

Granuloma Inguinale

Question 2

A person with the H/o long-term sexual relationship presented with painful ulcers on his genitals with tender lymphadenopathy. What is the diagnosis?

Accepted Answer

Chancroid

Answer

LGV

Answer

Chlamydia

Answer

Gonorrhoea

Question 3

A 45-year-old truck driver with a history of multiple sex partners presented to the dermatological department, as shown below. What is the likely diagnosis?

Accepted Answer

Secondary syphilis

Answer

Lichen planus

Answer

Scabies

Answer

Psoriasis

Question 4

A patient presents with erythematous streaks extending peripherally from a site of infection on the skin. Involvement of which of the following structures leads to this clinical presentation?

Accepted Answer

Superficial lymphatics

Answer

Skin

Answer

Superficial veins

Answer

Deep lymphatics

Question 5

A 45-year-old man with multiple sexual partners presents with a palmoplantar rash as seen below. On examination, he has epitrochlear lymphadenopathy. Which of the following is the likely diagnosis?

Accepted Answer

Secondary syphilis

Answer

Psoriasis

Answer

Meningococcemia

Answer

Stevens-Johnson syndrome

Question 6

A patient presents with an indurated plaque on the cheek with central atrophy. Chest X-ray reveals apical calcification. Which of the following tests is most appropriate to confirm the diagnosis?

Accepted Answer

PCR

Answer

Mantoux test

Answer

Slit skin smear

Answer

Probe test

Question 7

A male presents with lesions as shown in the image and a history of unprotected sexual intercourse a few months ago. What is the most appropriate investigation to confirm the diagnosis?

Accepted Answer

Serology

Answer

Tzanck smear

Answer

KOH

Answer

Biopsy

Question 8

Best drug for the condition shown below is: (NEET Jan 2018)

Accepted Answer

Doxycycline

Answer

Ivermectin

Answer

Sulphonamides

Answer

Penicillin

Question 9

The following lesion is diagnostic of:

Accepted Answer

Donovanosis

Answer

Syphilis

Answer

Chancroid

Answer

Herpes

Question 10

A 20-year-old patient presents with urethral discharge. What is the possible diagnosis?

Accepted Answer

Gonorrhea

Answer

Chlamydia trachomatis

Answer

Ureaplasma urealyticum

Answer

Trichomonas vaginalis

Bacterial Skin Infections — MCQs

Bacterial Skin Infections — MCQs

On this page

Practice by Chapter

Want unlimited practice?