Tropical Fungal Infections — MCQs
Which of the following is NOT a fungal infection?
A baby presents with recurrent ear infections with discharge, seborrheic dermatitis, hepatosplenomegaly, and cystic skull lesions. What is the most likely diagnosis?
A farmer presents you with a cauliflower-shaped mass on foot, which developed after a minor injury. Microscopy shows copper penny bodies. What is the most likely diagnosis?
A patient, a resident of Himachal Pradesh, presented with a series of ulcers in a row on his right leg. The biopsy from the affected area was taken and cultured on Sabouraud's dextrose agar. What is the most likely causative organism?
Bodies characteristic of chromoblastomycosis, also known as Medlar bodies, are typically found in which of the following?
Rhinosporidium seeberi is classified as a?
A 24 year old man had multiple, small hypopigmented macules on the upper chest and back for the last three months. The macules were circular, arranged around follicles and many had coalesced to form large sheets. The surface of the macules showed fine scaling. He had similar lesions one year ago which subsided with treatment. The most appropriate investigation to confirm the diagnosis is -
A patient presents with annular, scaly plaques with perifollicular extension on the trunk. What is the most likely diagnosis?
A 7 Year old boy with boggy swelling of the scalp with multiple discharging sinuses with cervical lymphadenopathy with easily pluckable hair. What would be done for diagnosis -
A child presents with multiple patchy areas of hair loss, scales, and itching. The sister also had similar lesions. What is the most likely diagnosis?
Tropical Fungal Infections Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is NOT a fungal infection?
- A. Black Piedra
- B. White Piedra
- C. Tinea nigra Palmaris
- D. Mycoses fungoides (Correct Answer)
Explanation: ***Mycoses fungoides*** - This is a type of **cutaneous T-cell lymphoma**, which is a **malignancy of lymphocytes**, not a fungal infection [1]. - It presents with skin lesions that can mimic various dermatological conditions but is characterized by abnormal T-cells infiltrating the skin [1], [2]. *Black Piedra* - This is a superficial fungal infection of the **hair shaft** caused by **Piedraia hortae**, forming hard, black nodules. - It is an example of a **dermatomycosis**. *White Piedra* - This is a fungal infection of the **hair shaft** caused by **Trichosporon species**, leading to soft, white to light brown nodules. - Like black piedra, it is also a **dermatomycosis**. *Tinea nigra Palmaris* - This is a superficial fungal infection of the **stratum corneum** of the skin, primarily on the palms and soles, caused by **Hortaea werneckii**. - It presents as irregular, darkly pigmented (brown to black) macules and is a true **mycosis**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 613-614. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 564-565.
Question 2: A baby presents with recurrent ear infections with discharge, seborrheic dermatitis, hepatosplenomegaly, and cystic skull lesions. What is the most likely diagnosis?
- A. Hemophagocytic lymphohistiocytosis
- B. Multiple myeloma
- C. Langerhans cell histiocytosis (Correct Answer)
- D. Acute lymphoblastic leukemia (ALL)
Explanation: ***Langerhans cell histiocytosis*** - This classic presentation involves a constellation of symptoms including **seborrheic dermatitis-like rash**, recurrent ear infections with discharge (due to infiltration of the mastoid bone), hepatosplenomegaly, and **cystic skull lesions**, all highly suggestive of Langerhans cell histiocytosis (LCH). - LCH is a rare disorder characterized by the proliferation of abnormal Langerhans cells, which can affect various organs and systems. *Hemophagocytic lymphohistiocytosis* - While patients with Hemophagocytic Lymphohistiocytosis (HLH) can present with **hepatosplenomegaly** and recurrent infections, they typically have high fevers, cytopenias, and poor clinical condition. - HLH does not typically cause **seborrheic dermatitis-like rashes** or **cystic bone lesions**. *Multiple myeloma* - Multiple myeloma is a **plasma cell malignancy** that predominantly affects older adults and is characterized by bone pain, anemia, renal failure, and hypercalcemia. - It does not present with recurrent ear infections, seborrheic dermatitis, or hepatosplenomegaly in this manner, and is exceedingly rare in infants. *Acute lymphoblastic leukemia (ALL)* - ALL is the most common childhood cancer and can cause **hepatosplenomegaly**, recurrent infections (due to neutropenia), and sometimes bone pain. - However, **seborrheic dermatitis-like rash** and **cystic skull lesions** are not typical features of ALL.
Question 3: A farmer presents you with a cauliflower-shaped mass on foot, which developed after a minor injury. Microscopy shows copper penny bodies. What is the most likely diagnosis?
- A. Sporotrichosis
- B. Blastomycosis
- C. Chromoblastomycosis (Correct Answer)
- D. Phaeohyphomycosis
Explanation: **Chromoblastomycosis** - The characteristic "cauliflower-shaped" lesion on the foot following a minor injury, especially in a farmer (indicating outdoor exposure), is highly suggestive of chromoblastomycosis. - The presence of **copper penny bodies** (also known as **sclerotic** or **muriform cells**) on microscopy is **pathognomonic** for chromoblastomycosis. *Blastomycosis* - Blastomycosis typically presents with **granulomatous lesions** that can ulcerate but are rarely described as cauliflower-shaped. - Microscopic examination would reveal **broad-based budding yeast cells**, not copper penny bodies. *Sporotrichosis* - Sporotrichosis usually presents as **subcutaneous nodules** that can ulcerate and spread lymphatically, forming a chain of lesions. - Microscopy shows **cigar-shaped budding yeasts** within macrophages or neutrophils, which are distinct from copper penny bodies. *Phaeohyphomycosis* - Phaeohyphomycosis encompasses a broad group of infections by dematiaceous fungi that produce **dark-walled hyphae** or yeast-like cells in tissue. - While it can cause subcutaneous nodules or cysts, the presence of distinct copper penny bodies points away from phaeohyphomycosis as the primary diagnosis.
Question 4: A patient, a resident of Himachal Pradesh, presented with a series of ulcers in a row on his right leg. The biopsy from the affected area was taken and cultured on Sabouraud's dextrose agar. What is the most likely causative organism?
- A. Cladosporium spp.
- B. Pseudoallescheria boydii
- C. Nocardia brasiliensis
- D. Sporothrix schenckii (Correct Answer)
Explanation: ***Sporothrix schenckii*** - The presentation of "ulcers in a row" on the leg is highly suggestive of **lymphocutaneous sporotrichosis**, a characteristic finding where the infection spreads via lymphatic drainage. - This fungus is endemic in certain regions including parts of **Himachal Pradesh**, and is typically acquired through contact with contaminated soil or plant material (e.g., rose thorns, sphagnum moss). - Grows well on **Sabouraud's dextrose agar**, producing characteristic colonies. *Cladosporium spp.* - While *Cladosporium* can cause **phaeohyphomycosis** or allergic fungal sinusitis, it does not typically present with the classic lymphocutaneous lesions described. - These fungi are common environmental contaminants and their infections are usually associated with chronic skin lesions, not a linear spread of ulcers. *Pseudoallescheria boydii* - *Pseudoallescheria boydii* is a common cause of **mycetoma** (Madura foot), characterized by chronic, destructive lesions with granulomas and sinus tracts that discharge grains. - This presentation is distinct from the linear ulcerative lesions described in the patient. *Nocardia brasiliensis* - *Nocardia brasiliensis* is a bacterium (an actinomycete) that causes **actinomycetoma**, characterized by chronic, suppurative lesions with sinus tracts discharging grains. - The characteristic **"ulcers in a row"** (lymphocutaneous spread pattern) is **not typical** of Nocardia infection, which presents as localized mycetoma rather than ascending lymphatic involvement. - While Nocardia can grow on some fungal media, the clinical presentation is the key distinguishing feature here.
Question 5: Bodies characteristic of chromoblastomycosis, also known as Medlar bodies, are typically found in which of the following?
- A. Asteroid bodies
- B. Torres bodies
- C. Sclerotic bodies (Correct Answer)
- D. Guarnieri bodies
Explanation: #### ***Sclerotic bodies*** * These are **dark brown, spherical, thick-walled fungi cells** that divide by septation, rather than budding. * They are often referred to as **Medlar bodies** or **muriform cells**, and their presence is diagnostic of **chromoblastomycosis**. #### *Asteroid bodies* * These are **eosinophilic star-like structures** found in granulomas, typically seen in **sporotrichosis** around fungal cells. * They are formed by the deposition of **antigen-antibody complexes** and host proteins on the surface of the fungal organism. #### *Torres bodies* * These are **eosinophilic intracytoplasmic inclusions** found in the neurons of the **hippocampus** and **cerebellum** in cases of **rabies**. * Their presence is a definitive diagnostic feature of rabies in affected brain tissue. #### *Guarnieri bodies* * These are **eosinophilic intracytoplasmic inclusions** seen in cells infected with **variola (smallpox) virus**. * They are characteristic of **poxvirus infections** and represent viral factories where replication occurs.
Question 6: Rhinosporidium seeberi is classified as a?
- A. Bacteria
- B. Mesomycetozoa (Correct Answer)
- C. Fungi
- D. Protozoa
Explanation: ***Mesomycetozoa*** - *Rhinosporidium seeberi* belongs to the **Mesomycetozoa** clade, formerly known as Ichthyosporea or DRIPs (Dermocystidium, Rosette agent, Ichthyophonus, Psorospermium). - This classification is based on **molecular phylogenetic analysis** which shows it as an aquatic obligate parasite, distinct from true fungi and protozoa. *Fungi* - While *Rhinosporidium seeberi* was historically and morphologically mistaken for a fungus, genetic analysis has revealed it is **not a true fungus**. - Its **cell wall composition** and **reproductive structures** differ significantly from those of true fungi. *Bacteria* - Bacteria are **prokaryotic organisms** lacking a membrane-bound nucleus and other organelles, which is fundamentally different from the eukaryotic structure of *Rhinosporidium seeberi*. - *Rhinosporidium seeberi* exhibits complex life cycles and **spore formation**, a characteristic not found in bacteria. *Protozoa* - Protozoa are typically **unicellular eukaryotic organisms** that are often motile and generally reproduce by fission. - *Rhinosporidium seeberi* has a more complex **multicellular developmental cycle** and growth form that distinguishes it from typical protozoa.
Question 7: A 24 year old man had multiple, small hypopigmented macules on the upper chest and back for the last three months. The macules were circular, arranged around follicles and many had coalesced to form large sheets. The surface of the macules showed fine scaling. He had similar lesions one year ago which subsided with treatment. The most appropriate investigation to confirm the diagnosis is -
- A. Potassium hydroxide preparation of scales (Correct Answer)
- B. Slit skin smear from discrete macules
- C. Skin biopsy of coalesced macules
- D. Tzanck test
Explanation: ***Potassium hydroxide preparation of scales*** - The description of **hypopigmented macules** with **fine scaling** on the upper chest and back, which coalesced and recurred, is highly suggestive of **Pityriasis versicolor** (also known as Tinea versicolor). - A **potassium hydroxide (KOH) preparation** of the scales directly visualizes the fungal elements (**hyphae and spores**, often described as "spaghetti and meatballs" appearance), confirming the diagnosis. *Slit skin smear from discrete macules* - A **slit skin smear** is primarily used for diagnosing mycobacterial infections, particularly **leprosy**, to detect acid-fast bacilli. - This procedure is not appropriate for diagnosing superficial fungal infections like Pityriasis versicolor. *Skin biopsy of coalesced macules* - While a **skin biopsy** can show fungal elements in the stratum corneum, it is an invasive and generally unnecessary procedure for diagnosing Pityriasis versicolor. - **KOH preparation** is a faster, simpler, and less invasive method that provides a definitive diagnosis. *Tzanck test* - The **Tzanck test** is used to identify multinucleated giant cells characteristic of viral infections, such as **herpes simplex virus** or **varicella-zoster virus**. - It involves scraping the base of a vesicle or bulla, which is not consistent with the described presentation of scaling macules.
Question 8: A patient presents with annular, scaly plaques with perifollicular extension on the trunk. What is the most likely diagnosis?
- A. Psoriasis
- B. Lichen planus
- C. Tinea (Correct Answer)
- D. Pityriasis versicolor
Explanation: ***Tinea*** - **Tinea corporis** classically presents with **annular, scaly plaques with central clearing** and an active, raised border. - On hairy areas or with follicular involvement, dermatophyte infections show **perifollicular extension** as the fungus invades hair follicles. - The **annular morphology with scale** is pathognomonic for dermatophyte infection, confirmed by **KOH preparation** showing septate hyphae. - Common sites include trunk, limbs, and any body area with hair follicles. *Psoriasis* - Presents with **well-demarcated, erythematous plaques** with **silvery-white scales**, typically on extensor surfaces (elbows, knees, scalp). - **Follicular psoriasis** is rare and shows **pinpoint follicular papules**, not annular plaques with perifollicular extension. - Auspitz sign (pinpoint bleeding on scale removal) helps differentiate from tinea. *Lichen planus* - Characterized by **pruritic, polygonal, purple, planar papules** (the "6 Ps"). - **Lichen planopilaris** (follicular variant) causes **scarring alopecia** with follicular hyperkeratosis, not annular scaly plaques. - Wickham striae may be visible on mucosal surfaces. *Pityriasis versicolor* - Caused by **Malassezia species**, presents as **hypo- or hyperpigmented macules** with fine scale on trunk and upper arms. - **Follicular variant** (pityriasis folliculorum) shows discrete follicular papules, NOT annular plaques. - "Spaghetti and meatballs" appearance on KOH prep (short hyphae and spores) differentiates from dermatophytes.
Question 9: A 7 Year old boy with boggy swelling of the scalp with multiple discharging sinuses with cervical lymphadenopathy with easily pluckable hair. What would be done for diagnosis -
- A. KOH mount (Correct Answer)
- B. Patch test
- C. Pus for culture
- D. Biopsy
Explanation: ***KOH mount*** - A **KOH mount** is the most appropriate initial diagnostic step for suspected **tinea capitis** with a **kerion** (boggy swelling, discharging sinuses, easily pluckable hair), as it allows for rapid visualization of fungal elements. - This test directly identifies **hyphae and spores** in hair shafts and scales, confirming a fungal infection. *Patch test* - A **patch test** is used to identify **contact allergens** in cases of **allergic contact dermatitis**, which presents with eczematous lesions, not boggy swelling and hair loss. - It involves applying small amounts of potential allergens to the skin and observing for a reaction after a period of time, which is irrelevant for a suspected fungal infection. *Pus for culture* - While a **bacterial culture** might be considered if a **secondary bacterial infection** is suspected, the primary diagnosis indicated by the symptoms (boggy swelling, easily pluckable hair) is fungal. - Culturing pus alone would miss the underlying fungal etiology and might lead to inappropriate treatment if bacteria are not the primary pathogen. *Biopsy* - A **skin biopsy** is an invasive procedure usually reserved for when less invasive tests are inconclusive or when conditions like **malignancy** or certain **inflammatory dermatoses** are suspected. - It is not the first-line diagnostic test for a clear case of suspected fungal infection like kerion, where **KOH mount** is rapid and effective.
Question 10: A child presents with multiple patchy areas of hair loss, scales, and itching. The sister also had similar lesions. What is the most likely diagnosis?
- A. Alopecia areata
- B. Tinea capitis (Correct Answer)
- C. Pediculosis capitis
- D. Pyoderma
Explanation: ***Tinea capitis*** - **Tinea capitis** presents with **patchy hair loss**, **scaling**, and **itching** on the scalp, which are classic signs of a fungal infection. - The fact that the sister also had similar lesions indicates a **contagious** condition, consistent with a **dermatophyte infection**. *Alopecia areata* - Characterized by **sudden, non-scarring hair loss** in circular or oval patches, often with no scaling or inflammation. - It is an **autoimmune condition** and typically not associated with itching or contagiousness amongst siblings. *Pediculosis capitis* - This condition involves an **infestation of head lice**, primarily causing **intense itching** of the scalp. - While it is contagious, it typically presents with **nits** (lice eggs) firmly attached to hair shafts and excoriations from scratching, rather than significant hair loss and scaling. *Pyoderma* - **Pyoderma** is a bacterial skin infection, often presenting as **pustules**, **crusts**, or **blisters** on the scalp. - While it can be contagious and cause discomfort, it is primarily characterized by purulent lesions and not the diffuse patchy hair loss and scaling seen in this case.
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