Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases with significant impairment of quality of life; traditionally, they have been thought to be mediated by polar helper T-cell subtypes 1 and 2 (T
H1 and T
H2), respectively.
1,2 Clinically, acute exacerbations of psoriasis and AD can result in erythroderma, a severe dermatitis characterized by diffuse erythema and scaling. Erythroderma represents a state of immune dysregulation and is a potential dermatologic emergency in some cases. Thus, rapid diagnosis and therapeutic control of the disease is essential.