Fungal Skin Infections Practice Questions

Q: Which of the following is NOT a characteristic of dermatophytosis?

Subdermal infection. ***Subdermal infection*** - Dermatophytosis, or **ringworm**, is characterized by infection of the **superficial keratinized tissues** (skin, hair, nails) and does not typically extend into the subdermal layers. - While fungal infections can be systemic or deep, dermatophytes specifically are restricted to the **stratum corneum** and other dead keratinized structures. *Scaly skin* - **Scaling** is a very common characteristic of dermatophyte infections due to the fungus proliferating within the **stratum corneum**, leading to increased epidermal turnover and shedding. - The scaling can be fine or coarse, often presenting in an **annular (ring-like)** pattern. *Itchy skin* - **Pruritus (itching)** is a prominent symptom of dermatophytosis, often leading patients to seek medical attention. - The itching can range from mild to severe, contributing to discomfort and potential secondary skin excoriations. *Superficial infection* - Dermatophytosis is by definition a **superficial fungal infection**, meaning it is confined to the outermost layers of the skin, hair, and nails. - These fungi produce enzymes such as **keratinases** that allow them to digest keratin, but they generally do not invade viable tissue below the epidermis.

Q: Kerion is a type of:

Fungal infection. ***Fungal infection*** - Kerion is a severe inflammatory **tinea capitis** (ringworm of the scalp) caused by a fungal infection. - It presents as a boggy, elevated, and painful lesion with pustules and could lead to **scarring alopecia**. *Viral infection* - Viral infections typically manifest with conditions like **herpes zoster**, **varicella**, or **molluscum contagiosum**, which have distinct clinical features and are not characterized as kerion. - Kerion's inflammatory, pustular nature and typical location on the scalp are not consistent with common viral dermatoses. *Bacterial infection* - Bacterial infections of the skin could cause conditions like **impetigo** or **folliculitis**, which are generally less extensive and lack the specific inflammatory boggy plaque typical of kerion. - While secondary bacterial infection can occur in kerion, the primary etiology is fungal, not bacterial. *Parasitic infection* - Parasitic infections of the scalp usually involve **lice** (pediculosis capitis) or **scabies**, which cause intense itching and excoriations but do not result in a kerion-like boggy, inflammatory mass. - The pathology of kerion involves a fungal invasion of hair follicles, distinct from parasitic infestation.

Q: An adult presents with oval, scaly, hypopigmented macules over the chest and back. The diagnosis is

Pityriasis Versicolor. ***Pityriasis Versicolor*** - This condition is caused by a **Malassezia species** yeast infection, presenting as characteristic **oval, scaly, hypopigmented or hyperpigmented macules** primarily on the trunk. - The hypopigmentation is often due to the production of **azelaic acid** by the yeast, which inhibits melanin synthesis. *Tuberculosis Cutis* - This refers to various skin manifestations of **tuberculosis**, which can include papules, nodules, ulcers, or verrucous lesions, often with significant inflammation or necrosis. - It does not typically present as widespread, oval, scaly, hypopigmented macules without other systemic signs of tuberculosis. *Psoriasis* - Characterized by **well-demarcated, erythematous plaques** covered with silvery scales, often found on extensor surfaces, scalp, and nails. - **Psoriasis** lesions are typically red and inflamed, not hypopigmented, and do not usually have the fine, scaly appearance described. *Granuloma Annulare* - Presents as **annular (ring-shaped) papules or plaques**, often flesh-colored, red, or pink, most commonly on the hands, feet, and ankles. - It is typically a **non-scaly eruption** and does not cause hypopigmented macules over the trunk.

Q: A 12-year-old girl presents with a well-defined annular pruritic lesion over the neck, with central clearing, that is gradually progressive over the last 8 months. The likely diagnosis is what?

Tinea corporis. ***Tinea corporis*** - This diagnosis is strongly supported by the presentation of a **well-defined, annular, pruritic lesion** with **central clearing**, which is characteristic of dermatophyte infections. - The gradual progression over 8 months is consistent with a chronic fungal infection in an otherwise healthy individual. *Cutaneous tuberculosis* - This condition typically presents with a **nodular, ulcerative, or verrucous lesion**, which is different from the annular lesion with central clearing described. - While it can be chronic, it is often associated with other signs of tuberculosis or immunosuppression, which are not mentioned. *Cutaneous leishmaniasis* - This typically presents as a **papule** enlarging into a **nodule, plaque, or ulcer**, often with a crusted center. - Although it can be chronic, its morphology is generally not described as an annular lesion with central clearing. *Psoriasis* - Psoriasis typically presents with **well-demarcated erythematous plaques** covered by **silvery scales**, usually without central clearing. - While it can be chronic and pruritic, the annular morphology with central clearing is not characteristic of typical psoriasis.

Q: What is the treatment for a baby brought to the clinic with a history of hair fall and a boggy scalp with easily pluckable hair, with a similar history occurring six months prior?

Oral griseofulvin. **Oral griseofulvin** - This presentation describes **tinea capitis**, a fungal infection of the scalp, characterized by **hair fall**, a **boggy scalp** (kerion), and **easily pluckable hair**. - **Oral griseofulvin** is the first-line and most effective systemic antifungal treatment for tinea capitis, particularly in children, due to its fungistatic action and accumulation in keratinized tissues. *Oral ketoconazole* - While an antifungal, **oral ketoconazole** is generally not recommended as the first-line treatment for tinea capitis in children due to concerns about **hepatotoxicity** and potential drug interactions. - **Griseofulvin** has a better safety profile and established efficacy for this condition. *Topical cotrimoxazole* - **Cotrimoxazole** is an antibiotic, not an antifungal, and thus would be ineffective against a fungal infection like tinea capitis. - Topical treatments alone are generally insufficient for tinea capitis because the infection is deep within the hair follicles. *Intralesional steroid* - **Intralesional steroids** are used to reduce inflammation in certain dermatological conditions, but they do not treat primary fungal infections. - Their use in tinea capitis, especially in the absence of an antifungal, could worsen the infection or lead to secondary complications due to immunosuppression.

Q: Tinea unguium affects

Nail plate. ***Nail plate*** - **Tinea unguium**, also known as **onychomycosis**, primarily affects the **nail plate**, causing discoloration, thickening, and crumbling. - The infection starts in the nail bed and invades the nail plate, often leading to **onycholysis** (separation of the nail from its bed). *Nail fold* - Infections of the **nail fold** are typically known as **paronychia**, which is often bacterial or yeast in origin. - While fungal infections can sometimes involve the nail folds, **tinea unguium** specifically refers to fungal infection of the nail plate itself, not primarily the surrounding skin. *Joints* - Fungal infections can rarely cause **septic arthritis**, but this is not what is referred to as **tinea unguium**. - **Tinea unguium** is a superficial fungal infection and does not involve the deeper structures like joints. *Inter digital space* - **Tinea pedis** (athlete's foot) commonly affects the **interdigital spaces** of the feet, causing itching, scaling, and cracking. - While **tinea pedis** can be a risk factor for developing **tinea unguium**, **tinea unguium** itself is specific to the nail and does not primarily manifest in the interdigital spaces.

Q: A patient presents with annular, scaly, itchy lesions with central clearing. The most likely causative organism is:

Trichophyton rubrum. ***Trichophyton rubrum*** - *Trichophyton rubrum* is the most common dermatophyte causing **tinea corporis** (ringworm), which characteristically presents as **annular, scaly, pruritic plaques with central clearing and an active raised border**. - The inflammatory response to fungal invasion of the stratum corneum produces the characteristic **pruritus and scaling**. - This classic "ringworm" morphology with centrifugal spread and central clearing is pathognomonic for dermatophyte infections. *Sporothrix schenkii* - Causes **sporotrichosis**, presenting as **painless subcutaneous nodules** that follow lymphatic channels (lymphocutaneous pattern). - Lesions are typically nodular and may ulcerate, not annular or scaly. - Usually follows traumatic inoculation, commonly in gardeners or florists. *Mycobacterium leprae* - Causes **leprosy** with **hypopigmented or erythematous patches** showing **loss of sensation** (anesthetic patches). - Nerve involvement leads to sensory loss, making itching uncommon. - The morphology is typically macular patches, not annular plaques with scaling. *Candida albicans* - Causes **intertrigo** and **candidiasis** presenting as **erythematous, moist, macerated patches** with **satellite pustules** in intertriginous areas (skin folds). - While pruritic, the morphology shows beefy-red patches with satellite lesions, not annular scaling plaques. - Typically occurs in warm, moist areas (groin, axillae, under breasts).

Q: An eleven-year-old boy has Tinea capitis on his scalp. Which of the following is the most appropriate line of treatment for this condition?

Oral griseofulvin therapy. ***Oral griseofulvin therapy*** - **Systemic antifungal agents** are essential for treating **Tinea capitis**, as the fungal infection is deep within the hair follicles and cannot be reached effectively by topical treatments alone. - **Griseofulvin** is a well-established and effective oral antifungal for **Tinea capitis** in children. *Shaving of the scalp* - While shaving the scalp might reduce some fungal load and facilitate topical treatment, it is **not a definitive treatment** for **Tinea capitis** on its own, as the infection remains deep in the hair follicles. - It does not address the underlying systemic nature of the infection within the hair shaft. *Topical griseofulvin therapy* - **Topical griseofulvin** is generally **ineffective** for **Tinea capitis** because the fungus resides deep within the hair follicle and hair shaft, where topical preparations cannot penetrate sufficiently. - **Systemic absorption** is required to deliver adequate drug concentrations to the site of infection. *Selenium sulphide shampoo* - **Selenium sulfide shampoo** can be used as an **adjunctive therapy** to reduce shedding of spores and prevent spread, but it is **not curative** for **Tinea capitis**. - It helps to reduce skin scaling and fungal burden on the surface but does not eradicate the infection deep within the hair follicles.

Q: What is the correct term for candidiasis of the penis?

Candidal balanitis. ***Balanitis*** - **Candidiasis of the penis** is specifically referred to as Candidal balanitis, an inflammatory condition affecting the **glans penis**. - This term accurately describes the location and cause of the infection. *Oral thrush* - **Oral thrush** is candidiasis of the mouth, characterized by **white patches** on the tongue and oral mucosa. - This term refers to a different anatomical location and is not applicable to penile infection. *No candidiasis present* - This option is incorrect because candidiasis can indeed affect the penis, leading to a recognized clinical condition. - Symptoms like **redness, itching, and discharge** would indicate the presence of candidiasis. *Leukoplakia* - **Leukoplakia** is a condition characterized by **white patches** that develop on the mucous membranes of the mouth, tongue, or sometimes the genitals. - It is a **precancerous lesion** that is not caused by Candida infection, distinguishing it from balanitis.

Q: In adult patients with multiple scaly macules over the chest and back, which single test is the most comprehensive for diagnosing pityriasis versicolor?

10% KOH mount. ***10% KOH mount*** - A **10% KOH mount** is the most comprehensive and definitive single test for diagnosing **pityriasis versicolor** as it directly visualizes the *Malassezia furfur* yeast in its characteristic **spaghetti and meatballs** appearance. - This microscopic examination confirms the presence of pathogenic fungi, distinguishing it from other dermatoses with similar clinical presentations. *Wood Lamp examination* - A Wood lamp examination can show **yellow-gold fluorescence** in affected areas, which is suggestive of *Malassezia furfur*. - However, not all *Malassezia* species or presentations will fluoresce, making it a supportive but not definitive diagnostic tool on its own. *Skin biopsy* - A **skin biopsy** is an invasive procedure and is usually not required for the diagnosis of pityriasis versicolor, which can be readily identified with simpler tests. - While it can confirm fungal elements, it's typically reserved for atypical or refractory cases where other diagnoses are being considered. *All of the options* - While a Wood lamp examination can be helpful and a skin biopsy could confirm the diagnosis, the question asks for the **most comprehensive single test**. - The 10% KOH mount directly identifies the causative organism, making it superior to the other options when only one test can be chosen.

Question 1

Which of the following is NOT a characteristic of dermatophytosis?

Accepted Answer

Subdermal infection

Answer

Scaly skin

Answer

Itchy skin

Answer

Superficial infection

Question 2

Kerion is a type of:

Accepted Answer

Fungal infection

Answer

Viral infection

Answer

Bacterial infection

Answer

Parasitic infection

Question 3

An adult presents with oval, scaly, hypopigmented macules over the chest and back. The diagnosis is

Accepted Answer

Pityriasis Versicolor

Answer

Tuberculosis Cutis

Answer

Psoriasis

Answer

Granuloma Annulare

Question 4

A 12-year-old girl presents with a well-defined annular pruritic lesion over the neck, with central clearing, that is gradually progressive over the last 8 months. The likely diagnosis is what?

Accepted Answer

Tinea corporis

Answer

Cutaneous tuberculosis

Answer

Cutaneous leishmaniasis

Answer

Psoriasis

Question 5

What is the treatment for a baby brought to the clinic with a history of hair fall and a boggy scalp with easily pluckable hair, with a similar history occurring six months prior?

Accepted Answer

Oral griseofulvin

Answer

Oral ketoconazole

Answer

Intralesional steroid

Answer

Topical cotrimoxazole

Question 6

Tinea unguium affects

Accepted Answer

Nail plate

Answer

Nail fold

Answer

Joints

Answer

Inter digital space

Question 7

A patient presents with annular, scaly, itchy lesions with central clearing. The most likely causative organism is:

Accepted Answer

Trichophyton rubrum

Answer

Sporothrix schenkii

Answer

Mycobacterium leprae

Answer

Candida albicans

Question 8

An eleven-year-old boy has Tinea capitis on his scalp. Which of the following is the most appropriate line of treatment for this condition?

Accepted Answer

Oral griseofulvin therapy

Answer

Shaving of the scalp

Answer

Topical griseofulvin therapy

Answer

Selenium sulphide shampoo

Question 9

What is the correct term for candidiasis of the penis?

Accepted Answer

Candidal balanitis

Answer

Oral thrush

Answer

No candidiasis present

Answer

Leukoplakia

Question 10

In adult patients with multiple scaly macules over the chest and back, which single test is the most comprehensive for diagnosing pityriasis versicolor?

Accepted Answer

10% KOH mount

Answer

All of the options

Answer

Skin biopsy

Answer

Wood Lamp examination

Fungal Skin Infections — MCQs

Fungal Skin Infections — MCQs

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