Dermatologists from Perth suspect anaerobic bacteria may be responsible for four cases of hyperkeratotic erythema in the groin, which all responded “dramatically” to amoxicillin-clavulanic acid.

Writing in the Australasian Journal of Dermatology, they describe the cases of three women and a man who presented with inguinal rashes that did not respond to topical steroids, antifungals or flucloxacillin.

“Our four cases were referred to us as cases unresponsive to treatment and had similar clinical presentations with migratory hyperkeratotic scaly erythematous eruptions involving skin of the groins, upper thighs and sometimes the buttocks,” the authors said.

The man’s rash had been present for 10 months; two of the women had had a rash for seven months each; while the third woman’s skin condition had been present for two months.