Practical Dermatology Editorial Board member Adam Friedman, MD, FAAD, presented “When It’s Not Eczema?” at The Dermatology Education Foundation’s DEF Essential Resource Meeting 2024 (DERM2024) NP/PA CME Conference.
Dr. Friedman noted that eczema is a clinical diagnosis, so therefore looking/assessing for all essential, important and common features are central to making the right diagnosis. Under appreciated clues include pityriasis alba, keratosis pilaris, ichthyosis vulgaris, hyperlinear palms, perifollicular changes such as follicular accentuation, ocular/periorbital changes, and perioral/periauricular lesions.
“There is an incredible spectrum of clinical presentations,” Dr. Friedman said. “One common feature is that plaques are usually poorly defined/demarcated, whereas psoriasis or papulosquamous dermatoses are well demarcated.
Dr. Friedman stated his opinion that it is not AD unless there is pruritus. “Things in the eczematous spectrum absolutely feel good to scratch, which I believe is unique and distinguishing about this category” he said. If the distribution of the rash is atypical and/or conventional therapy does not appear effective despite patient adherence, he added, an alternative diagnosis should be considered.
Cutaneous T-cell lymphoma (CTCL), for example, is often missed and misdiagnosed as eczema. It can be pruritic (thank you il-31) but is often asymptomatic. The distribution is often sun protected areas, not to mention it does not match that of textbook AD. For CTCL not one, but several biopsies of steroid untreated x 3 weeks sites are needed to find the rogue atypical lymphocyte. Dr. Friedman noted that CTCL, among other chronic inflammatory skin diseases can be “great mimickers, and this may in turn warrant a biopsy but please consider from where you sample to get the most out of it.,” Dr. Friedman said, though he cautioned not to biopsy elbows, hands, feet as these areas often yield the dreaded and somewhat useless “spongiotic psoriasiform dermatitis.”
If a diagnosis of CTCL is made, Dr. Friedman said, options for early-stage MF include topical corticosteroids, nitrogen mustard, topical bexarotene, and nbUVB. Options for refractory early-stage CTCL include PUVA or NBUVB and/or oral bexarotene (low-dose).
Other common mimickers include contact dermatitis, dermatophytosis, which can be identified through a bedside potassium hydroxide prep, seborrheic dermatitis, lichen planus, scabies, and many more!
Disclaimer: This content was developed independently and is not endorsed by the DEF or DERM2024.