Derms likely to misdiagnose fungal infections on visual inspection

Even dermatologists are likely to misdiagnose fungal infections by sight, as these can be hard to distinguish from inflammatory skin diseases, including secondary syphilis, annular psoriasis and pityriasis rosea, according to Adam Friedman, M.D., associate professor, director of the residency program, and director of translational research in dermatology at the George Washington University School of Medicine and Health Sciences.

Dr. Friedman and co-presenters surveyed dermatologists during a presentation on fungal skin infections at the 2016 Orlando Dermatology Aesthetic & Clinical Conference in Florida. They asked dermatologists in attendance to look at 13 clinical images and determine whether or not each was a fungal skin infection, anonymously providing a simple yes or no answer. In results published November in the Journal of the American Academy of Dermatology, the researchers found half the dermatologists classified a majority, or eight of 13, cases correctly. Participating dermatologists accurately categorized the cases with 75 percent accuracy in four of the 13 cases. And only one of the cases, a clinical image of gram-negative toe web infection, was accurately identified by more than 90 percent of the audience.

“We really pride ourselves on being the masters of identifying disease through visual inspection. The concept of doorway diagnosis is very much from dermatology,” Dr. Friedman tells Dermatology Times. “The problem with dermatophyte infections-superficial skin infections caused by fungal agents-is that they can look like many different things. And the same is true for non-fungal skin infections.”

Dr. Friedman says the misdiagnoses can have big consequences in dermatology practice. Dr. Friedman says he had a patient who came to him with cutaneous lymphoma but had been misdiagnosed for months prior.

“We have to remind ourselves that these conditions can be highly variable and that we need to use our toolbox to really make the right diagnosis because missing the diagnosis obviously means a delay in care and possible morbidity associated with not initiating the right treatment,” he says.

The survey findings reflect answers from between 15 and 33 participants, who responded as they came in and out of the session. The presenters recorded the answers and crunched the data.

“A large percentage of the audience was consistently giving the wrong answers,” Dr. Friedman says.

Images that stumped many in the audience included one of a deep fungal infection, called a Majocchi granuloma, which, when it tracks down the hair follicles, goes deeper and is a little nodular.

“It looks like a bacterial infection or could mimic a sarcoidosis, even,” he says. “Twenty of 23 got that wrong and said it was not a fungal infection. These conditions usually don’t follow the classic patterns. There were some conditions that we put up there that weren’t fungal infections and people thought they were, including Pityriasis rosacea, secondary syphilis. Sixteen of 17 said the syphilis image was a fungal infection, which it is not.”

The take-home message, according to Dr. Friedman, is it’s important to use basic skills, beyond the visual diagnosis, when diagnosing many skin conditions.

Even something as simple as a potassium hydroxide prep is often a lost art, Dr. Friedman says.

“Often people will be quick to give a cream, instead of proving the diagnosis. That can’t happen,” he says. “Do your scrapings, use your cultures and biopsy, if you’re wondering. And it’s important that if there are any questions about your own skill sets, to take advantage of opportunities to strengthen and maintain these skills at conferences, CME activities ….”

Disclosures: Dr. Friedman reports no relevant disclosures.