What Explains This Itchy Rash?

Author:
David L. Kaplan, MD—Series Editor

Citation:
Kaplan DL. What explains this itchy rash? Consultant. 2017;57(9):536-537.

This 45-year-old man presented with a 1- to 2-month history of an extremely pruritic photodistributed rash that had started in the late spring. He denied any exposure history, taking any new medications, and using any new colognes or new personal products. Physical examination revealed coalescing lichenoid papules with some hyperpigmentation and areas of excoriation.

Answer on next page

Answer: Actinic reticuloid

Results of a skin biopsy revealed the diagnosis of actinic reticuloid, also called chronic actinic dermatitis and persistent light reaction. This condition generally begins with persistent erythema of sun-exposed areas. Severe pruritus of the affected area is a hallmark of the disease process, and the lesions and associated symptoms worsen with sun exposure. As the condition progresses, lichenification occurs; however, papules and plaques may be seen. The evolution of this condition may be linked to a patient’s work outdoors and thus to the degree of UV radiation exposure. Nevertheless, severe disease can persist during winter months despite decreased sun exposure.

Complete avoidance of sun exposure is essential, since sunscreens are rarely effective in cases of actinic reticuloid. Hydroxychloroquine is not effective, and patients generally rely on corticosteroids for relief or utilize steroid-sparing agents to avoid chronic corticosteroid use. A biopsy is often necessary to make the diagnosis, while the results of laboratory studies can exclude some diagnoses. 

David L. Kaplan, MD, is a clinical assistant professor of dermatology at the University of Missouri–Kansas City School of Medicine in Kansas City, Missouri, and at the University of Kansas School of Medicine in Kansas City, Kansas. He practices adult and pediatric dermatology in Overland Park, Kansas.