# Pityriasis Rubra Pilaris in an Atopic Dermatitis Patient: A Case Report

## TL;DR

A 43-year-old woman with atopic dermatitis developed atypical pityriasis rubra pilaris, which cleared after two months of UVB phototherapy and remained in remission for two years.

## Contribution

This case report highlights the successful long-term management of atypical PRP in a patient with atopic dermatitis using narrowband UVB phototherapy.

## Key findings

- The patient showed complete clearance of skin lesions after two months of NBUVB treatment.
- Lesions remained clear for two years during follow-up.
- Skin biopsy confirmed the diagnosis of atypical adult PRP (type II).

## Abstract

Pityriasis rubra pilaris (PRP) is a rare, chronic, inflammatory papulosquamous skin disease. Here, we report a case of a 43-year-old female with a known history of atopic dermatitis, bronchiectasis, and goiter who presented with a six-month history of persistent itchy skin lesions on her extremities. A skin examination revealed multiple diffuse, well-defined, fine, scaly erythematous patches with areas of spared skin over all four extremities, along with palmoplantar keratoderma. The trunk was spared. The differential diagnosis included atopic eczema, pityriasis rubra pilaris, dermatomyositis, mycosis fungoides, parapsoriasis, psoriasis, and drug-induced eczematous dermatitis. A skin biopsy revealed hyperkeratosis, acanthosis, spongiosis, follicular plugging, and mild perivascular lymphohistiocytic cellular infiltrates in the dermis. Based on the clinicopathological findings, the patient was diagnosed with atypical adult pityriasis rubra pilaris (PRP) (type II). She was started on narrowband UVB phototherapy (NBUVB). Two months after starting NBUVB treatment, all the skin lesions had cleared. She was put under periodic follow-up, and the lesions have remained clear for two years up to the time of this publication.