This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Skin
Which is used in keratinised skin: 
Select and explain. 
A. Salicylic acid, B. Fluconazole, C. Steroids, D. Coal tar
A: Salicylic acid
Answer: A: Salicylic acid 
Explanation: Ans: a (Salicylic acid) Ref: Tripathi, 5th ed, p.Keratolytics dissolve the intercellular substance in the homy layer of the skin.The epidermal cells swell, soften & then desquamate.These drugs are used on hyperkeratotic lesions like corns, warts, psoriasis, chronic dermatitis, ringworm& athletes foot.They include:a. Salicylic acid- as 10-20% solution in alcohol or propylene glycol for dissolving com.b. Resorcinol- It has antiseptic, antifungal, local irritant & keratolytic properties.