Fungal Skin Infections Practice Questions

Q: The image shows a KOH mount suggestive of diagnosis of:

Pityriasis versicolor. ***Pityriasis versicolor*** - The image clearly shows a KOH mount with **short, curved hyphae** and **clusters of round yeast cells**, characteristic of **spaghetti and meatballs** appearance, which is pathognomonic for *Malassezia furfur*, the causative agent of pityriasis versicolor. - This common superficial fungal infection presents as hypo- or hyperpigmented patches, primarily on the trunk, neck, and arms, and is diagnosed by this distinctive microscopic finding. *Tinea imbricata* - This is a rare form of tinea corporis caused by *Trichophyton concentricum*, characterized by **concentric, scaly rings**. - A KOH mount would show **long, branching hyphae** without the characteristic yeast clusters seen in the image. *Pompholyx* - **Pompholyx** (dyshidrotic eczema) is an endogenous eczematous condition characterized by **deep-seated vesicles** and bullae on the palms, soles, and sides of the fingers. - It is a non-infectious condition, and a KOH mount would show **no fungal elements**; instead, it would reveal inflammatory cells if any scraping were done. *Tinea capitis* - **Tinea capitis** is a dermatophyte infection of the scalp and hair, primarily affecting children. - A KOH mount from hair or scalp scrapings would show **arthrospores** (either endothrix or ectothrix) and **hyphae within or around the hair shaft**, not the yeast and short hyphae clusters characteristic of *Malassezia*.

Q: Which of the following is not effective against this condition?

Griseofulvin. ***Griseofulvin*** - The image shows **Pityriasis Versicolor**, characterized by hyperpigmented or hypopigmented patches with fine scaling, caused by *Malassezia furfur*. - Griseofulvin is an oral antifungal primarily used for **dermatophyte infections** (tinea infections) of the skin, hair, and nails, and is not effective against *Malassezia furfur*. *Topical Ketoconazole* - **Ketoconazole** is a broad-spectrum azole antifungal that is highly effective against a wide range of fungi, including *Malassezia furfur*. - It works by inhibiting the synthesis of **ergosterol**, a crucial component of fungal cell membranes, leading to cell death. *Topical selenium sulphide* - **Selenium sulfide** is an effective antifungal agent commonly used in shampoos and lotions to treat conditions like dandruff and **Pityriasis Versicolor**. - It works by reducing the growth of *Malassezia furfur* and has **keratolytic** properties, helping to shed the affected skin cells. *Topical sulfur preparations* - **Sulfur** has antifungal, antibacterial, and keratolytic properties, making it useful in treating various skin conditions. - Topical sulfur preparations are effective in treating **Pityriasis Versicolor** by inhibiting fungal growth and promoting exfoliation of the affected epidermis.

Q: All are true about the image shown except:

KOH mount will show pseudohyphae. ***Correct: KOH mount will show pseudohyphae*** - This is the **EXCEPTION** because dermatophytes (causative agents of tinea capitis) produce **TRUE SEPTATE HYPHAE**, not pseudohyphae - **Pseudohyphae** are characteristic of **Candida species** (yeast infections), not dermatophyte infections - In tinea capitis, KOH mount shows **arthroconidia and septate hyphae** within and surrounding the hair shaft - This is a fundamental distinction in medical mycology that differentiates dermatophyte from yeast infections *Incorrect: Sparse hair* - Tinea capitis characteristically presents with **alopecia and broken hair shafts** - The fungal infection weakens hair, causing it to break at the scalp surface, creating patches of hair loss with "black dots" (broken hair stumps) - This is a hallmark clinical feature seen in the image *Incorrect: Can be associated with cervical lymphadenopathy* - **Inflammatory tinea capitis** (kerion type) frequently causes **regional lymphadenopathy** - Cervical and posterior auricular nodes commonly enlarge due to the immune response to the fungal infection - This is an expected finding in moderate to severe cases *Incorrect: Wood's lamp shows green fluorescence* - Some species causing tinea capitis do show **green fluorescence** under Wood's lamp - **Microsporum canis** and **M. audouinii** exhibit bright green fluorescence - However, **Trichophyton species** (most common in many regions) do NOT fluoresce - While not universally present, this statement is TRUE for ectothrix infections caused by Microsporum species

Q: The cup-shaped yellow crusts shown in the image are called:

Scutula. ***Scutula*** - The image shows **cup-shaped, yellow crusts** formed around hair shafts, which are characteristic findings of scutula. - Scutula are pathognomonic for **tinea capitis favosa (favus)**, a severe form of fungal infection of the scalp, most often caused by *Trichophyton schoenleinii*. *Favus* - Favus is the **specific type of tinea capitis** characterized by the formation of scutula, which are visible in the image. - While it's the underlying disease, the question asks for the specific lesion shown, which is the scutula. *Kerion* - **Kerion** is an inflammatory, painful, boggy plaque with pustules and crusting that can lead to scarring alopecia. - It does not present as the distinct **cup-shaped yellow crusts** seen in the image. *Seborrheic dermatitis* - **Seborrheic dermatitis** presents with greasy, yellowish scales on an erythematous base, commonly on the scalp, face, and chest. - It does not typically form the well-demarcated, **cup-shaped scutula** observed in this image.

Q: A child has been brought with the following scalp lesion with history of itching in scalp and hair loss for past 2 months. Which of the following is useful for diagnosis of this patient? (AIIMS May 2017)

KOH mount. ***KOH mount*** - The image shows a **patch of hair loss** with visible scaling on the scalp, along with a history of itching, which is highly suggestive of **tinea capitis (ringworm of the scalp)**. - A **KOH (potassium hydroxide) mount** is the most common and effective initial diagnostic test for fungal infections of the skin, hair, and nails, as it helps visualize fungal elements (hyphae and spores). *Gram stain* - **Gram stain** is primarily used to identify **bacterial infections** by differentiating bacteria based on their cell wall composition. - It is not useful for diagnosing **fungal infections** like tinea capitis. *Slit skin smear* - A **slit skin smear** is a diagnostic technique mainly used for the detection of **Mycobacterium leprae** in cases of **leprosy**. - It is not relevant for diagnosing common fungal scalp infections. *Tzanck smear* - A **Tzanck smear** is used to identify **multinucleated giant cells** and **acantholytic cells**, characteristic findings in **herpes simplex**, **varicella zoster**, and other blistering viral conditions. - This method is not used for the diagnosis of **fungal infections** of the scalp.

Q: A 35-year-old presented with a single warty lesion on the foot after a thorn prick. No regional lymph nodes are seen. Biopsy shows the following lesion. Diagnosis is:

Chromoblastomycosis. ***Chromoblastomycosis*** - The image reveals characteristic **sclerotic bodies** (also known as Medlar bodies or copper pennies), which are thick-walled, septate, dematiaceous (pigmented) fungal cells, pathognomonic for chromoblastomycosis. - The history of a **single warty lesion** on the foot after a **thorn prick** is typical for subcutaneous fungal infections caused by traumatic inoculation of dematiaceous fungi, leading to chromoblastomycosis. *Sporotrichosis* - Characterized by **cigar-shaped budding yeasts** in tissue and a **lymphocutaneous spread** (multiple nodules along lymphatic channels), which is not mentioned or depicted. - While it can follow a thorn prick, the microscopic findings (sclerotic bodies) are not consistent with sporotrichosis. *Madura foot* - Also known as mycetoma, it typically presents with **multiple draining sinuses** discharging pus and grains (microcolonies of the causative organism). - Histologically, it shows **"grains"** composed of fungal hyphae or bacteria, surrounded by a distinct inflammatory reaction, which is different from the sclerotic bodies seen in the image. *Botromycosis* - This is a **bacterial infection** that mimics fungal mycetoma, presenting with tumefaction, draining sinuses, and grains. - The grains in botryomycosis are composed of bacterial colonies, not fungi, and the histological appearance would differ significantly from the pigmented fungal bodies seen.

Q: A 35-year-old presented with a single warty lesion on the foot after a thorn prick. No regional lymph nodes are seen. Biopsy shows the following lesion. Treatment is?

Itraconazole. **Itraconazole** - The clinical presentation of a **warty lesion on the foot** after a **thorn prick**, along with the biopsy showing **chromoblastomycosis (dark-staining fungal cells or sclerotic bodies)**, indicates a fungal infection. **Itraconazole** is a first-line systemic antifungal agent for such infections. - **Chromoblastomycosis** is typically treated with systemic antifungals, with itraconazole being effective due to its broad spectrum and good tissue penetration. *Amikacin plus cotrimoxazole* - **Amikacin** is an aminoglycoside antibiotic, and **cotrimoxazole** is a combination antibiotic (sulfamethoxazole and trimethoprim). - These medications are used to treat **bacterial infections** and are ineffective against fungal pathogens. *Ciclopirox* - **Ciclopirox** is a topical antifungal agent primarily used for superficial fungal infections like **tinea corporis** or **onychomycosis**. - Given the deep-seated nature of chromoblastomycosis and its occurrence after a penetrating injury, a topical agent would likely be insufficient. *Amorolfine* - **Amorolfine** is a topical antifungal lacquer primarily used for the treatment of **onychomycosis (nail fungal infections)**. - It is not indicated for deep cutaneous or subcutaneous fungal infections like chromoblastomycosis, which requires systemic treatment.

Q: Which of the following is the most appropriate treatment for the skin condition shown in the image?

Selenium sulphide. ***Selenium sulphide*** - The image shows **pityriasis versicolor** (tinea versicolor), characterized by hypopigmented/hyperpigmented macules with fine **branny scaling** caused by **Malassezia furfur**. - **Selenium sulphide** is the **first-line topical treatment** for pityriasis versicolor, effectively eliminating the causative yeast organism. *Terbinafine* - **Terbinafine** has **limited topical efficacy** for pityriasis versicolor compared to selenium sulphide or ketoconazole. - While it's an effective antifungal for **dermatophytes**, it's not the preferred agent for **Malassezia** infections. *Tacrolimus* - **Tacrolimus** is a **calcineurin inhibitor** used primarily for **atopic dermatitis** and inflammatory skin conditions. - The image shows a **fungal infection** (pityriasis versicolor), not an inflammatory eczematous condition requiring immunosuppression. *Erythromycin* - **Erythromycin** is a **macrolide antibiotic** used for bacterial infections, not fungal conditions. - Pityriasis versicolor is caused by a **yeast organism** (**Malassezia furfur**), requiring antifungal treatment, not antibiotics.

Q: What is the diagnosis of the lesion visible in neck folds of this child?

Intertriginous candida. ***Intertriginous candida*** - The image shows **erythema, scaling, and white satellite lesions** in a skin fold, which is characteristic of candidal intertrigo. - This condition thrives in **warm, moist environments** like neck folds of infants, often presenting with burning and itching. *SSSS* - **Staphylococcal Scalded Skin Syndrome (SSSS)** is characterized by widespread **erythema and superficial blistering**, leading to skin peeling, which is not seen here. - It usually involves a more diffuse rash and often has a **positive Nikolsky sign**, unlike the localized lesion shown. *Impetigo* - **Impetigo** typically presents with **honey-colored crusts** and is caused by bacterial infection, primarily *Staphylococcus aureus* or *Streptococcus pyogenes*. - While it can occur in skin folds, the characteristic white, cheesy appearance and satellite lesions seen in the image are not typical of impetigo. *Ecthyma* - **Ecthyma** is a more severe, ulcerative form of impetigo, characterized by **punched-out ulcers with adherent crusts** that extend into the dermis. - The lesion in the image does not show the deep ulceration or dense, dark crusts associated with ecthyma.

Q: A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?

Sporotrichosis. ***Sporotrichosis*** - This presentation, an **ulcerative nodule with purulent discharge** on a finger after a **thorn prick** in a gardener, is classic for **sporotrichosis** (rose gardener's disease). - The organism, *Sporothrix schenckii*, is found in soil, plants, and decaying vegetation and typically enters through **skin trauma**. *Chromoblastomycosis* - Characteristically presents with **verrucous (warty) plaques or nodules** that slowly enlarge; it does not typically show the ulcerative nodule with purulent discharge found here. - While it can be acquired through trauma, the **morphology of the lesions** differs from the described case. *Phaeohyphomycosis* - This is a broad term for infections caused by dematiaceous (pigmented) fungi that typically present as **subcutaneous cysts, abscesses, or nodules**, but the specific clinical picture of **lymphocutaneous spread** following trauma is less characteristic than sporotrichosis. - The lesions tend to be more **encapsulated or abscess-like** rather than the ulcerative, purulent nodule described. *Mycetoma* - Mycetoma presents as a **chronic, localized, progressively destructive infection** of the skin, subcutaneous tissue, fascia, and bone, often characterized by **swelling, draining sinuses, and grains** (microcolonies of the causative organism). - While it can be acquired via trauma, the typical presentation is much more **extensive and chronic** than the initial ulcerative nodule described.

Question 1

The image shows a KOH mount suggestive of diagnosis of:

Accepted Answer

Pityriasis versicolor

Answer

Tinea imbricata

Answer

Pompholyx

Answer

Tinea capitis

Question 2

Which of the following is not effective against this condition?

Accepted Answer

Griseofulvin

Answer

Topical Ketoconazole

Answer

Topical selenium sulphide

Answer

Topical sulfur preparations

Question 3

All are true about the image shown except:

Accepted Answer

KOH mount will show pseudohyphae

Answer

Sparse hair

Answer

Can be associated with cervical lymphadenopathy

Answer

Wood's lamp shows green fluorescence

Question 4

The cup-shaped yellow crusts shown in the image are called:

Accepted Answer

Scutula

Answer

Favus

Answer

Kerion

Answer

Seborrheic dermatitis

Question 5

A child has been brought with the following scalp lesion with history of itching in scalp and hair loss for past 2 months. Which of the following is useful for diagnosis of this patient? (AIIMS May 2017)

Accepted Answer

KOH mount

Answer

Gram stain

Answer

Slit skin smear

Answer

Tzanck smear

Question 6

A 35-year-old presented with a single warty lesion on the foot after a thorn prick. No regional lymph nodes are seen. Biopsy shows the following lesion. Diagnosis is:

Accepted Answer

Chromoblastomycosis

Answer

Sporotrichosis

Answer

Madura foot

Answer

Botromycosis

Question 7

A 35-year-old presented with a single warty lesion on the foot after a thorn prick. No regional lymph nodes are seen. Biopsy shows the following lesion. Treatment is?

Accepted Answer

Itraconazole

Answer

Amikacin plus cotrimoxazole

Answer

Ciclopirox

Answer

Amorolfine

Question 8

Which of the following is the most appropriate treatment for the skin condition shown in the image?

Accepted Answer

Selenium sulphide

Answer

Terbinafine

Answer

Tacrolimus

Answer

Erythromycin

Question 9

What is the diagnosis of the lesion visible in neck folds of this child?

Accepted Answer

Intertriginous candida

Answer

SSSS

Answer

Impetigo

Answer

Ecthyma

Question 10

A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?

Accepted Answer

Sporotrichosis

Answer

Chromoblastomycosis

Answer

Phaeohyphomycosis

Answer

Mycetoma

Fungal Skin Infections — MCQs

Fungal Skin Infections — MCQs

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