A 28-year-old factory worker develops sharply demarcated depigmented patches confined to the dorsum of both feet and the sides of the toes, exactly corresponding to the contact areas of his rubber footwear. Which chemical is the most likely causative agent?
- A p-Phenylenediamine
- B Hydroquinone monobenzyl ether
- C Para-tertiary butylphenol ✓
- D Mercuric chloride
Correct answer: C. Para-tertiary butylphenol
Explanation
Chemical leukoderma from rubber articles such as footwear, adhesives, and black rubber products is classically caused by para-tertiary butylphenol (PTBP), a potent melanocytotoxic compound. The distribution matching the contact area of rubber sandals is diagnostic. Monobenzyl ether of hydroquinone causes intentional therapeutic depigmentation, p-phenylenediamine causes allergic contact dermatitis, and mercurials cause hyperpigmentation, eliminating the other options.
Reference: Rook's Textbook of Dermatology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.