Onychomycosis — MCQs
All are nail changes seen in cases of psoriasis except:
Which drug can be given as a nail lacquer treatment in onychomycosis?
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?
Tinea unguium affects
A 70 year old farmer, presented to you with complaints of yellowish discolouration of his finger nails for the past 6 months, he also gives history of recurrent episodes of itching in the groin for which he used to take local home made herbal remedy. On examination 3 of his toe nails also show similar change with tunneling. Which among the following is the best test for rapid confirmation of your diagnosis?
Which of the following statements is incorrect regarding nail changes in various conditions?
Which one of the following is the correct description of Mee's lines, seen in chronic arsenic poisoning?
A 30-year-old washerwoman presents with the following lesion. All are correct except:
Cutis marmorata occurs due to exposure to –
Skin scraping and KOH mounting is done for what condition?
Onychomycosis Indian Medical PG Practice Questions and MCQs
Question 1: All are nail changes seen in cases of psoriasis except:
- A. Subungual hyperkeratosis
- B. Oil drop sign
- C. Mees lines (Correct Answer)
- D. Pitting
Explanation: ***Mees lines*** - **Mees lines** (or Aldrich-Mees lines) are **transverse white bands** that appear in the nail plate. - They are typically associated with **heavy metal poisoning** (e.g., arsenic), chemotherapy, or systemic illnesses, not psoriasis. *Subungual hyperkeratosis* - This is a common finding in **psoriasis**, characterized by the **thickening of the nail bed** due to excessive keratin production. - It leads to lifting of the nail plate from the nail bed. *Oil drop sign* - The **oil drop sign** (or salmon patch) is a classic psoriatic nail change, presenting as a **translucent, yellowish-red discoloration** under the nail plate. - It is due to psoriasis of the nail bed. *Pitting* - **Nail pitting** refers to the presence of **small depressions or pits** on the nail surface. - It results from defective keratinization of the nail matrix and is a characteristic sign of nail psoriasis.
Question 2: Which drug can be given as a nail lacquer treatment in onychomycosis?
- A. Terbinafine
- B. Ciclopirox olamine (nail lacquer) (Correct Answer)
- C. Nystatin
- D. Itraconazole
Explanation: ***Ciclopirox olamine (nail lacquer)*** - **Ciclopirox olamine** is an antifungal agent formulated as a nail lacquer, specifically designed for topical application in **onychomycosis**. - Its mechanism involves interfering with fungal cellular processes, transported directly to the nail bed where the fungal infection resides. *Terbinafine* - **Terbinafine** is primarily an **oral antifungal** medication or available as a topical cream, but not typically in a nail lacquer formulation for onychomycosis. - While highly effective against dermatophytes causing onychomycosis, its systemic absorption is key to its efficacy when administered orally. *Nystatin* - **Nystatin** is an antifungal agent primarily effective against **Candida** species and is not typically used for dermatophyte-induced onychomycosis, nor is it commonly formulated as a nail lacquer. - Its broad spectrum is limited in this context, as most onychomycosis cases are caused by dermatophytes, which are less susceptible to nystatin. *Itraconazole* - **Itraconazole** is a **systemic antifungal** medication, effective in treating onychomycosis, but it is not available as a nail lacquer. - It works by inhibiting fungal cytochrome P450 enzymes, which are critical for ergosterol synthesis, a component of the fungal cell membrane.
Question 3: 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. Pus for culture
- B. Biopsy
- C. KOH mount (Correct Answer)
- D. None of the options
Explanation: ***KOH mount*** - A **KOH mount** (potassium hydroxide wet mount) is the most appropriate **initial rapid diagnostic test** for suspected **tinea capitis** with **kerion formation**, allowing immediate visualization of fungal elements (hyphae and spores). - The clinical presentation of boggy scalp swelling, discharging sinuses, cervical lymphadenopathy, and easily pluckable hair is classic for **kerion**, a severe inflammatory form of tinea capitis caused by dermatophytes (commonly *Trichophyton* or *Microsporum* species). - KOH mount is **quick, inexpensive, and readily available**, making it ideal for immediate diagnosis in clinical practice, though fungal culture may be performed subsequently for species identification. *Pus for culture (bacterial)* - While bacterial culture might be performed to rule out **secondary bacterial infection**, it does not diagnose the underlying **fungal etiology** of kerion. - The primary pathogen in kerion is a dermatophyte fungus, not bacteria, though secondary bacterial infection can occur. *Biopsy* - A **biopsy** is usually reserved for cases that are atypical, treatment-resistant, or when there is diagnostic uncertainty with other conditions (e.g., dissecting cellulitis, bacterial abscess). - It is an **invasive procedure** and not the first-line diagnostic approach for a clinically obvious case of kerion. *None of the options* - Given the classic clinical presentation of kerion, a definitive diagnostic method (KOH mount) is required to confirm the fungal infection and guide appropriate systemic antifungal treatment. - Therefore, choosing "None of the options" would be incorrect.
Question 4: Tinea unguium affects
- A. Nail fold
- B. Nail plate (Correct Answer)
- C. Joints
- D. Inter digital space
Explanation: ***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.
Question 5: A 70 year old farmer, presented to you with complaints of yellowish discolouration of his finger nails for the past 6 months, he also gives history of recurrent episodes of itching in the groin for which he used to take local home made herbal remedy. On examination 3 of his toe nails also show similar change with tunneling. Which among the following is the best test for rapid confirmation of your diagnosis?
- A. Tzanck smear
- B. KOH mount (Correct Answer)
- C. Woods lamp
- D. Biopsy
Explanation: ***KOH mount*** - A **KOH mount** (potassium hydroxide) dissolves keratinocytes, allowing for direct visualization of fungal elements such as **hyphae** and **spores** under a microscope. This is the **most rapid and cost-effective test** for confirming fungal infections like **onychomycosis**. - The patient's presentation with **yellowish discoloration** and **"tunneling"** of nails (suggesting onycholysis and subungual hyperkeratosis), along with a history of recurrent groin itching (potentially **tinea cruris**), strongly points to a fungal infection. *Tzanck smear* - A **Tzanck smear** is primarily used to detect multinucleated giant cells in **herpesvirus infections** (e.g., herpes simplex, varicella-zoster). - It is not useful for identifying fungal elements responsible for nail discoloration or suspected onychomycosis. *Woods lamp* - A **Woods lamp** uses ultraviolet light to detect specific fluorescent substances, particularly useful for diagnosing certain **bacterial infections** (e.g., *Corynebacterium minutissimum* in erythrasma) or some **tinea capitis** species (*Microsporum*). - Most common dermatophytes causing onychomycosis **do not fluoresce** under a Wood's lamp, making it an unreliable diagnostic tool in this scenario. *Biopsy* - A **nail biopsy** (with histology and special stains like PAS) is a highly accurate diagnostic method for onychomycosis, especially when other tests are inconclusive. - However, it is an **invasive procedure**, takes more time for results, and is generally not the **most rapid** initial test compared to a KOH mount.
Question 6: Which of the following statements is incorrect regarding nail changes in various conditions?
- A. Onycholysis is seen in Psoriasis.
- B. Mees lines are indicative of Arsenic poisoning.
- C. Pterygium of nails is associated with Lichen Planus.
- D. Koilonychia is associated with Vitamin B12 deficiency. (Correct Answer)
Explanation: ***Koilonychia is associated with Vitamin B12 deficiency.*** - **Koilonychia**, or "spoon nails," is primarily associated with **iron deficiency anemia**, not Vitamin B12 deficiency. - In Koilonychia, the nails become **thin, brittle**, and concave in shape. *Onycholysis is seen in Psoriasis.* - **Onycholysis** refers to the separation of the nail plate from the nail bed, which is a common nail finding in **psoriasis**. - Other nail changes in psoriasis include **pitting**, oil spots, and subungual hyperkeratosis. *Mees lines are indicative of Arsenic poisoning.* - **Mees lines** are transverse white lines or bands that appear across the nail plate, characteristic of severe illness or poisoning. - They are classically associated with **arsenic poisoning**, but can also be seen in other conditions like thallium poisoning or kidney failure. *Pterygium of nails is associated with Lichen Planus.* - **Pterygium unguis** involves the forward growth of the proximal nail fold (cuticle) onto the nail plate, leading to fusion. - It is a prominent and often distinguishing feature of **lichen planus** affecting the nails, which can lead to permanent nail deformity or loss.
Question 7: Which one of the following is the correct description of Mee's lines, seen in chronic arsenic poisoning?
- A. Transverse white lines on the skin of palms and soles
- B. Transverse white lines on nails of fingers and toes (Correct Answer)
- C. Transverse red lines on the nails of fingers and toes
- D. Transverse red lines on the skin of palms and soles
Explanation: ***Transverse white lines on nails of fingers and toes*** - **Mee's lines** are characteristic **white transverse bands** seen specifically on the **nails** of the fingers and toes. - They are typically associated with **arsenic poisoning** but can also be seen in other systemic illnesses. *Transverse white lines on the skin of palms and soles* - While chronic arsenic poisoning can cause **skin pigmentation changes** (melanosis) and **hyperkeratosis** on the palms and soles, it does not typically manifest as distinct white transverse lines on the skin. - Mee's lines are exclusively a **nail finding**. *Transverse red lines on the nails of fingers and toes* - **Red lines on nails** are not characteristic of Mee's lines; Mee's lines are described as **white**. - Red nail changes, such as splinter hemorrhages, are often associated with other conditions, like **endocarditis**. *Transverse red lines on the skin of palms and soles* - This description does not correspond to Mee's lines, which are **white nail changes**, nor is it a typical manifestation of chronic arsenic poisoning on the skin in this specific pattern. - Skin manifestations of arsenic poisoning on palms and soles are usually **hyperpigmentation** and **hyperkeratosis**.
Question 8: A 30-year-old washerwoman presents with the following lesion. All are correct except:
- A. Rule out diabetes mellitus in recurrent episodes
- B. Deformed nail plate
- C. Tinea unguium (Correct Answer)
- D. Caused by normal commensal of GIT
Explanation: ***Tinea unguium*** - **Tinea unguium** (onychomycosis) is a **dermatophyte infection** of the nail plate, typically caused by *Trichophyton* species, not *Candida*. - The image shows **chronic paronychia** caused by *Candida* affecting the nail fold, which is a completely different condition from tinea unguium. *Caused by normal commensal of GIT* - *Candida albicans* is indeed a **normal commensal** of the gastrointestinal tract and can cause chronic paronychia in washerwomen. - Constant **water exposure** allows this opportunistic organism to colonize and infect the periungual tissues. *Rule out diabetes mellitus in recurrent episodes* - **Recurrent candidal infections** warrant screening for **diabetes mellitus** due to impaired immune function and elevated glucose levels. - Diabetic patients have increased susceptibility to **opportunistic fungal infections** including chronic paronychia. *Deformed nail plate* - The image clearly shows **nail dystrophy** with irregular, discolored, and thickened nail plate secondary to chronic inflammation. - **Chronic paronychia** affects the nail matrix, leading to **abnormal nail growth** and permanent deformation.
Question 9: Cutis marmorata occurs due to exposure to –
- A. Cold temperature (Correct Answer)
- B. Dust
- C. Hot temperature
- D. Humidity
Explanation: ***Cold temperature*** - **Cutis marmorata** is a physiological response to **cold temperatures**, characterized by a mottled, reticulated vascular pattern on the skin. - This occurs due to **vasoconstriction** of the small arteries and arterioles, alongside **vasodilation** of the venules, creating the characteristic marbled appearance. *Dust* - Exposure to **dust** typically causes **irritation**, allergic reactions, or respiratory issues, such as **dermatitis**, **contact urticaria**, or **asthma**. - It does not directly lead to the characteristic vascular changes seen in cutis marmorata. *Hot temperature* - **Hot temperatures** generally cause **vasodilation** in the skin to facilitate **heat dissipation**, leading to redness and warmth. - This is the opposite physiological response to cutis marmorata, which involves vasoconstriction. *Humidity* - **Humidity** primarily affects **skin hydration** and the rate of perspiration, potentially exacerbating certain skin conditions like **eczema** or **fungal infections**. - High or low humidity does not directly induce the vascular changes that result in cutis marmorata.
Question 10: Skin scraping and KOH mounting is done for what condition?
- A. Leprosy
- B. Varicella
- C. Fungal infections (Correct Answer)
- D. Herpes Simplex Virus (HSV)
Explanation: **Explanation:** **1. Why Fungal Infections is Correct:** Potassium Hydroxide (KOH) mounting is the **gold standard bedside diagnostic test** for superficial fungal infections (Dermatophytosis, Candidiasis, and Tinea versicolor). The medical principle relies on the fact that KOH is a strong alkali that digests keratin, epithelial cells, and debris in skin scrapings, hair, or nails. Since fungal cell walls contain **chitin**, they remain resistant to KOH. This allows the clinician to clearly visualize fungal elements like hyphae, spores, or budding yeast under a microscope. **2. Why Other Options are Incorrect:** * **Leprosy (A):** Diagnosis is primarily clinical, supported by **Slit Skin Smear (SSS)** using Modified Ziehl-Neelsen staining to identify *Mycobacterium leprae* (acid-fast bacilli). * **Varicella (B) & HSV (D):** These are viral infections. The classic bedside test for these is the **Tzanck Smear**, where a scraping from the base of a vesicle is stained (Giemsa/Wright) to look for **multinucleated giant cells** (Acantholytic cells). **3. High-Yield Clinical Pearls for NEET-PG:** * **Concentration:** 10% KOH is used for skin/hair; 20% KOH is used for thicker nail clippings. * **Classic Morphologies:** * **Dermatophytes:** Translucent, branching, septate hyphae. * **Tinea Versicolor:** "Spaghetti and meatballs" appearance (short hyphae and spores). * **Candidiasis:** Pseudohyphae and budding yeast cells. * **Modification:** **DMSO (Dimethyl sulfoxide)** can be added to KOH to speed up the clearing of keratin without requiring heat.
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