Photosensitive atopic dermatitis exacerbated by UVB exposure.

Photosensitive atopic dermatitis (AD) is a rare disease entity that many physicians are not familiar with, thus it often is misdiagnosed. It can be life altering, as patients often strictly avoid the sun and may only leave the house at night. Effective treatments are available, and therefore diagnosis is key to improve quality of life for these patients. We describe a case of photosensitive AD exacerbated by UVB exposure. The diagnosis was made with phototesting, and the patient was able to begin treatment with narrowband UVB (NB-UVB) hardening while on immunosuppression. The literature on photosensitive AD is limited, and this entity typically is not found in the main dermatology textbooks. Our case emphasizes the diagnostic problems and complexity of photosensitive AD. Histopathologic findings are nonspecific. A thorough history and physical examination can provide the necessary clues for further workup. Phototesting should be performed to confirm the diagnosis and evaluate the degree of sensitivity to UV light and the specific wavelength eliciting the cutaneous response. Photoprovocation and photopatch testing also can be useful to confirm the diagnosis.