KOHALA COAST, HAWAII — Dermatophytes are common copathogens in nails with pseudomonas infection or in abnormal-looking nails with psoriasis, Boni E. Elewski, M.D., said at a conference on clinical dermatology sponsored by the Center for Bio-Medical Communication Inc.
Look twice to catch onychomycosis in patients with green nails typical of bacterial infection with pseudomonas, she suggested. It's reasonable to assume that a green-nailed patient has pseudomonas and to treat it with a quinolone antibiotic. A culture for onychomycosis at this stage will be negative because pseudomonas inhibits the growth of dermatophytes, although a potassium hydroxide (KOH) test probably will be positive for dermatophytes.
To be sure, see the patient again after you've eradicated the pseudomonas to check for onychomycosis, said Dr. Elewski, professor of dermatology at the University of Alabama, Birmingham.
When Dr. Elewski sees a patient whose psoriasis doesn't warrant systemic treatment but whose nails look abnormal, she cultures the nails for fungus.