A Rare Case of Peripheral Edema Induced by Topical Minoxidil: A Case Report.

Introduction: Minoxidil, initially developed as an oral antihypertensive, is widely used topically for hair regrowth. Off-label applications, such as beard enhancement, have gained popularity. While generally safe, systemic absorption of topical minoxidil can lead to rare side effects, like peripheral edema.

Case presentation: A 17-year-old male developed peripheral edema seven weeks after starting topical minoxidil 5% to promote beard growth. Initially, he experienced mild headaches in the fifth week, which resolved spontaneously. By the seventh week, he noticed swelling, which was exacerbated by prolonged immobility. Diagnostic evaluations, including Doppler ultrasound, echocardiography, ECG, and blood tests, were unremarkable. Edema resolved completely one to two weeks after discontinuation of minoxidil.

Conclusion: Minoxidil's vasodilatory mechanism, which supports hair growth, can also lead to systemic effects, like peripheral edema due to fluid retention and increased capillary hydrostatic pressure. While rare with topical formulations, systemic absorption is influenced by factors, such as application area, concentration, and individual skin permeability. This case highlights a rare but clinically significant systemic side effect of topical minoxidil.