Question:
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: For diagnosis of dermatophytosis the clinical materials such as skin scrapings, hairs and nails can be observed under microscope by wet mount preparation with 5% KOH
Reason R: The KOH acts as a clearing agent which digests the proteinaceous host cell debris and leaves the sugar containing fungal cell wall
In light of the above statements, choose the correct answer from the options given below:
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: For diagnosis of dermatophytosis the clinical materials such as skin scrapings, hairs and nails can be observed under microscope by wet mount preparation with 5% KOH
Reason R: The KOH acts as a clearing agent which digests the proteinaceous host cell debris and leaves the sugar containing fungal cell wall
In light of the above statements, choose the correct answer from the options given below:
Assertion A: For diagnosis of dermatophytosis the clinical materials such as skin scrapings, hairs and nails can be observed under microscope by wet mount preparation with 5% KOH
Reason R: The KOH acts as a clearing agent which digests the proteinaceous host cell debris and leaves the sugar containing fungal cell wall
In light of the above statements, choose the correct answer from the options given below:
Show Hint
KOH acts as a clearing agent by hydrolyzing host proteins (keratin) while leaving the alkali-resistant fungal cell walls (chitin) intact for microscopic visualization.
Updated On: Aug 13, 2026
- Both A and R are true and R is the correct explanation of A
- Both A and R are true but R is NOT the correct explanation of A
- A is true but R is false
- A is false but R is true
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Understanding the Concept:
Dermatophytosis (ringworm) is a superficial fungal infection of keratinized tissues (skin, hair, claws) caused by genera such as Microsporum and Trichophyton.
Direct microscopic examination of clinical specimens is a rapid diagnostic tool.
Detailed Explanation:
Let us analyze both statements:
- Assertion A: Direct wet mounts using Potassium Hydroxide (KOH) are used to examine skin scrapings, hair, and nails for dermatophytes. Treating the sample with a KOH solution (ranging from 5% up to 20%) clears the specimen, allowing fungal hyphae and arthroconidia to be visualized under a light microscope. Thus, Assertion A is true.
- Reason R: KOH is a strong alkali that digests and dissolves the proteinaceous host keratin and cellular debris present in the sample. In contrast, the fungal cell walls are composed of chitin and complex beta-glucans (polysaccharides), which are highly resistant to alkali hydrolysis. As a result, the host tissue is cleared, leaving the intact, refractive fungal structures clearly visible. Thus, Reason R is true and provides the biochemical explanation for using KOH.
Step 2: Final Answer:
Both A and R are true, and R is the correct explanation of A.
Dermatophytosis (ringworm) is a superficial fungal infection of keratinized tissues (skin, hair, claws) caused by genera such as Microsporum and Trichophyton.
Direct microscopic examination of clinical specimens is a rapid diagnostic tool.
Detailed Explanation:
Let us analyze both statements:
- Assertion A: Direct wet mounts using Potassium Hydroxide (KOH) are used to examine skin scrapings, hair, and nails for dermatophytes. Treating the sample with a KOH solution (ranging from 5% up to 20%) clears the specimen, allowing fungal hyphae and arthroconidia to be visualized under a light microscope. Thus, Assertion A is true.
- Reason R: KOH is a strong alkali that digests and dissolves the proteinaceous host keratin and cellular debris present in the sample. In contrast, the fungal cell walls are composed of chitin and complex beta-glucans (polysaccharides), which are highly resistant to alkali hydrolysis. As a result, the host tissue is cleared, leaving the intact, refractive fungal structures clearly visible. Thus, Reason R is true and provides the biochemical explanation for using KOH.
Step 2: Final Answer:
Both A and R are true, and R is the correct explanation of A.
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