TLDR Minoxidil can cause erythema multiforme, even if patch tests are negative.
A case was reported in 1993 of a male developing erythema multiforme after using topical minoxidil for androgenetic alopecia. The condition recurred upon reapplication of the minoxidil solution and also after taking minoxidil orally, confirming the drug as the cause. However, a patch test with minoxidil was negative, indicating a complex reaction mechanism.
85 citations
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January 2007 in “Journal of Drug Targeting” Liposomes better deliver minoxidil for hair loss treatment than niosomes.
397 citations
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February 2004 in “British Journal of Dermatology” Minoxidil boosts hair growth by opening potassium channels and increasing cell activity.
33 citations
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June 1995 in “Journal of Pharmaceutical Sciences” More ethanol increases minoxidil delivery, but too much lowers efficiency.
20 citations
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March 1994 in “Clinical and Experimental Dermatology” Too much topical minoxidil can cause excessive hair growth, but stopping treatment reverses it.
40 citations
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May 1987 in “The Lancet” Minoxidil helps some bald men, but most lose hair again when stopping.
14 citations
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April 1987 in “PubMed” Topical minoxidil can promote hair growth in men with hereditary hair loss, with no serious side effects.