Coexisting problems impede identification/treatment of onychomycosis
Nail abnormalities could decrease cure rate, expert says
Denver — Treating severe onychomycosis successfully often requires addressing coexisting nail problems as well, an expert says.
Rarely does any dermatophyte infection occur without clinical presentation of nail dystrophy, says Avner Shemer, M.D. He is a senior physician and specialist in skin and venereal diseases, dermatologic surgery and dermatomycology at the Chaim Sheba Medical Center, Tel Hashomer, Israel.
Yeasts or non-dermatophyte molds with clinical presentation of onychomycosis could be pathogens provided that no dermatophytes are found in three separate cultures taken two weeks apart, he says.
“Yeasts and/or molds without clinical presentation of onychomycosis are usually saprophytes,” Dr. Shemer says.
Around 50 percent of nail problems that present to dermatologists involve purely onychomycosis, he says.
“The other 50 percent involve other nail abnormalities such as nail psoriasis, trauma or onycholysis. When a patient has onychomycosis and other nail abnormalities, usually it decreases the cure rate for onychomycosis,” he says.
In clinical studies, Dr. Shemer says that despite strict inclusion and exclusion criteria, “You never know if a patient experienced nail trauma 20 years ago.” Enrolling such a patient could distort results.
Somewhat similarly, he says, a patient could have a non-dermatophyte infection that has nothing to do with his or her onycholysis.
“Treating the non-dermatophyte infection will not help the onycholysis,” Dr. Shemer says.
The secondary infection on top of the onycholysis is usually a pathogen (such as a saprophyte) or contaminant. Less common causes of onycholysis include fungus, he says.
Conversely, the combination of onychomycosis and nail trauma occurs particularly commonly in the fifth toenail.
“Antifungal treatment will not necessarily result in a total cure,” Dr. Shemer says.