Unilateral Koilonychia Secondary to Chemical Depilatory Product.

Excess hair is a problem for both men and women who want to conform to today's cosmetic social norms. Chemical depilatories are a safe, fast, and inexpensive method of hair removal. The most commonly used depilatory agents are thioglycolates and to a lesser extent, sulphides. The most common side effect of chemical depilatories is irritant contact dermatitis. However, allergic contact dermatitis is rare and may be related to lanolin, fragrance, or thioglycolate itself. Unilateral koilonychia as a side effect of chemical depilatories has not been described previously in the literature. We report this case due to its rarity and highlight the significance of nail protection while using chemical depilatory products.