Allergic Contact Dermatitis from Minoxidil

In the document, a case of allergic contact dermatitis from the use of a 2% minoxidil solution is reported. A 22-year-old male with androgenic alopecia developed symptoms including burning, pruritus, and red papules and vesicles on his scalp, neck, and eyebrows after using the solution for 3 weeks. Patch testing showed a negative response to the standard series but a positive reaction to the minoxidil lotion. Five control subjects tested negative with the same lotion. The document suggests that while minoxidil's sensitizing potential is low, its increasing use for various types of alopecia may lead to more cases of allergic contact dermatitis. The document also briefly mentions allergic contact dermatitis from a Chinese herbal preparation named Yunnan Paiyao, but the main focus is on the minoxidil case.