As a pediatric dermatologist, Dr. Robert A. Silverman is all too familiar with this scenario: A child is referred to him with a diagnosis of nail fungus, and the parents are frustrated that the oral antifungal agents did not work.
What bothers him the most is not the antifungals, but that the patients didn’t need them to begin with because the child didn’t have a fungal infection, he said at the annual Hawaii Dermatology Seminar, sponsored by Skin Disease Education Foundation (SDEF). Several conditions of the nail in children can easily be mistaken for fungal infections.
Dr. Silverman of the department of pediatrics at Georgetown University Medical Center in Washington discussed how to distinguish fungal disease mimics from other pediatric nail conditions in children.
Onychomycosis, the most common nail infection in adults, is not all that common in children, Dr. Silverman said. Studies have shown the prevalence in children to be less than 3% in developed countries, although it is increased among children who have Down syndrome and HIV, or children from households with moccasintype Trichophyton rubrum. Clinical variants are similar to those that occur in adults, such as white superficial onychomycosis, distal lateral subungual onychomycosis, proximal subungual onychomycosis, and endonyx onychomycosis.
Other conditions that may be mistaken for fungal infections include:
• Psoriasis. Nail findings in patients who have psoriasis can be misinterpreted as fungal disease. Telltale signs of psoriasis in the nails, however, are large, irregular pits and the oil spot sign.
• Subungual tumors. These include subungual exostosis and onychomatricoma. These benign growths push on the skin surface, leading to separation of the nail. "Some people think fungus when it’s really a tumor of the underlying bone," Dr. Silverman said.
• Pachyonychia congenita. Though often confused with fungal disease, this condition, which involves a single thickened toenail, is somewhat rare. "If someone came in with a thick toenail, I’d culture him or her," Dr. Silverman said. "If the culture is negative, then you have to start thinking of these other conditions."
• Alopecia areata. Children may have nail signs of alopecia areata before hair loss occurs. In alopecia areata, the nail surface is studded to near confluence with tiny pits, also known as Scotch plaid nails. Also, the nail will have lost its luster and has a sandpaperlike texture.
"If you see what looks like alopecia areata of the nail, but don’t see any hair findings, you ought to scrape the nail to rule out fungus, because fungus can look like alopecia areata of the nails," Dr. Silverman said. "And, of course, then you would want to treat it."
Treatment for fungal infections requires the use of an oral agent for 6-12 weeks, so Dr. Silverman emphasized the importance of obtaining a culture. "If you’re going to treat someone for that length of time, it makes sense to know exactly what you’re treating," he said.
Also, Dr. Silverman said, any time he sees that a child’s parent appears to have a fungal infection, he considers that to be a red flag when trying to diagnose the patient.