When it looks and itches like atopic dermatitis. But isn’t.
Additional steps and investigation can assist in diagnosis.
Atopic dermatitis is one of the most common diagnoses in dermatology, and with good reason. Much of the time, the diagnosis really is that simple — except for those times when things aren’t as they appear.
There are multiple other inflammatory, autoimmune, and systemic disorders that can present in much the same way as AD, and knowing when to look beyond that initial diagnosis can be the key to getting the best outcome for your patients.
Making the distinction between AD and another condition often comes down to the two greatest tools used by dermatologists: patient history and physical exams, said Raj Chovatiya, MD, PhD, FAAD, director of the Center for Eczema and Itch and medical director of the Clinical Trials Unit, and assistant professor of dermatology at the Northwestern University Feinberg School of Medicine in Chicago, during the March 19 session, “Itch Tales: The Challenges of Diagnosing Atopic Dermatitis.”
“Atopic dermatitis is a clinical diagnosis (as are many other mimickers), meaning that biopsy, laboratory testing, or imaging are not necessary for making the diagnosis,” he said. “A detailed history with the right questions can make a big difference along with an appreciation for nuanced findings on the skin. However, in difficult cases, careful use of additional diagnostics can make all the difference when it comes to including and excluding the right dermatoses on the differential diagnosis.”
Searching beneath the surface
Even something as seemingly simple as diaper dermatitis can present as AD.
Peter Lio, MD, FAAD, clinical assistant professor of dermatology and pediatrics at the Northwestern University Feinberg School of Medicine in Chicago, said he has seen many cases of patients with rashes in the diaper area that mimicked AD.
“I think the issue is that because AD is so common, and because it is heterogeneous, it can become something of a ‘wastebasket diagnosis’ in some situations,” he said. “By that I mean, if it is even remotely eczematous but it’s not entirely clear what it is, it may be easier to just call it AD and start treatment. Eczematous dermatitis — comprising AD, seborrheic dermatitis, nutritional deficiencies, and other rashes that are red, scaly, and sometimes oozing or weeping — can be confusing.”
Dr. Lio said in one particular case of diaper dermatitis, the real culprit came from a surprising place. “For that case, we noted the presence of Koebnerization,” he said. “It was appearing in areas that had been scratched. This is not typical of AD, but it is sometimes seen in nutritional deficiencies. This prompted a review of (the patient’s) total parenteral nutrition, and it was found that zinc was being accidentally omitted. With zinc added back, everything cleared up within a few days. It was remarkable.”
Take the time you need to diagnose
JiaDe (Jeff) Yu, MD, MS, FAAD, assistant professor of dermatology and director of contact and occupational dermatitis at Massachusetts General Hospital in Boston, said he encountered a case of an 8-month-old baby who reportedly had a history of AD since birth as well as a history in the family. But after initial treatments didn’t work, a little more digging was necessary.
“He failed to improve with topical steroids and needed repeated systemic steroids for improvement,” Dr. Yu said. “This is not typical for AD and should prompt consideration for another etiology. He was checked for viral and bacterial infection, which were all negative. Ultimately, he made it to me for patch testing — the gold standard for evaluation of allergic contact dermatitis. We found several relevant positive reactions in the products being used to treat his dermatitis, including the topical steroids. Avoidance led to significant improvement.”
Ultimately, Dr. Chovatiya said, it comes down to taking the time to make the right diagnosis.
“We’re living through the greatest era of AD research, and we finally have safe, targeted options for our patients, with many more to come,” he said. “However, the right therapies only work for the right diagnosis. If you treat incorrectly, your patients aren’t going to get better, and you may create new problems. Although AD is common, every single patient with inflamed skin, eczematous changes, and pruritus does not have AD. Always keep a broad perspective before homing in on the diagnosis.”
Other presenters included Joaquin C. Brieva, MD, FAAD, Joan Guitart, MD, George Han, MD, PhD, FAAD, Theodore Rosen, MD, FAAD, and Elizabeth A. Swanson, MD, FAAD.
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