Difficult-to-diagnose cases and the lessons learned

8-year-old with blistering rash on foot before and after eventual accurate diagnosis and treatment plan. (Photo:Matthew J. Zirwas, M.D.)

Dermatologist Matthew J. Zirwas, M.D., saw an 8-year-old girl who had a blistering rash on one foot for three years.

“She had seen 21 prior physicians, including a well-known pediatric dermatologist, the best-known patch tester in the United States, dermatologists, pediatric infectious disease doctors at one of the top three pediatric hospitals in the country, multiple podiatrists and even a psychiatrist to deal with pain and learn coping strategies,” Dr. Zirwas says.

The child’s foot pain was so bad that she slept in bed with her parents for three years. The pain kept her from walking, so she rode to where she had to go in a wagon.

The foot rash ruined her parents’ lives and the girl’s childhood.

Dr. Zirwas first assessed patient and family dynamics to make sure this wasn’t self-induced or the child wasn’t seeking attention. After meeting with the patient and family, Dr. Zirwas was convinced that it was a bona fide dermatology case.  

Next, he studied what had been done and didn’t work to rule out possibilities. The other providers who had seen the patient were smart people, so it was safe to think they didn’t miss the obvious possibilities, he says.

Dr. Zirwas concluded there were no known entities resulting in unilateral foot dermatitis that hadn’t been evaluated and treated.

“She had several inpatient stays for IV antibiotics. She had been sedated for an MRI of the foot. She had complete removal of the great toenail, while she was awake and screaming. That was sent for fungus culture. She has had multiple biopsies while awake and sedated. She has had over a dozen topical treatments, primarily topical steroids, topical antifungals, mupirocin and systemic steroids. She had multiple courses of systemic steroids and rebounded after,” Dr. Zirwas says.

Dr. Zirwas thought about what might be left that could cause a blistering rash like hers on only one foot.

“The only thing I could come up with was that she has a persistent colonization with one or more organisms that her immune system is reacting to,” he says. “When I see things like this I’m expecting it to be either a multi-agent or an unusual organism that doesn’t respond to normal stuff. She has had antibiotics, antifungals and none of those have really worked. So, it’s not something to which I can use an normal approach.”

Dr. Zirwas decided to treat the condition as an interdigital, two web infection, which is something usually seen in older adults. The condition has multiple organisms, including yeast, fungus and different bacteria types.

“A normal antibiotic or any normal agent isn’t going to work to kill all of that stuff,” Dr. Zirwas says. “So, as my initial step, I put her on oral terbinafine for two weeks and had her start using topical betadine because topical betadine is very broad spectrum and will kill yeast, fungus and all kinds of bacteria. As a kid, she’s not going to mind having an orange foot from the betadine staining the skin.”

The patient responded to the treatment. Within a couple of weeks, she was substantially improved. Dr. Zirwas stopped the oral terbinafine after the two weeks but kept the patient on the topical betadine for two months, until her foot was clear. Today, the patient applies a skin sanitizer with 24-hour activity to prevent relapse, he says.

Dr. Zirwas’s diagnosis: poly microbial skin colonization with super antigen producing organisms.

The patient’s foot has been clear for the first time in years. The family lives hours away from Dr. Zirwas’s Bexley, Ohio, practice but continues to email the dermatologist about the child’s progress. The patient plays in the park with the other kids and attends school full time, which wasn’t the case prior to treatment. She’s also sleeping in her own room.

Dr. Zirwas says the lesson for dermatology providers is to think outside the box. Thinking outside the box doesn’t mean making a weird diagnosis or using an exotic treatment. Rather, it means taking into consideration what hasn’t worked, considering what else it could be and what can be done about each of those possibilities, then, trying the most likely.

“If the first approach hadn’t worked, I would have thought, OK, this isn’t an infection. And I would have tried something else therapeutically. Probably in her case that would have meant methotrexate or cyclosporin, but fortunately we didn’t have to go that way,” Dr. Zirwas says.