Abstract Number: 205

A case of facial discoid dermatosis – a novel type of Pityriasis rubra pilaris?

M. Liau

Meeting: 2021 Dermcoll

Session Information

Date: -

Session Title: Poster Presentations

Session Time: -

A 39-year-old Chinese male presented with a 10-year history of asymptomatic rash over his face. He was otherwise well and had no periorbital region, forehead and cheeks. There was no nail or joint involvement. Histopathological examination revealed hyperkeratosis, focal parakeratosis and psoriasi- form hyperplasia with an intact granular layer. There was a mild superficial perivascular and dermal inflammatory infil- trate. Other histological features of psoriasis including suprapapillary thinning and dilated capillaries were absent. Overall histological features were in keeping with pityriasis rubra pilaris (PRP). He tried the following topical treatments with no improvement: hydrocortisone 1%, mometasone, pimecrolimus, tacrolimus, ketoconazole. He declined sys- temic medications and was subsequently lost to follow-up.

Facial discoid dermatosis (FDD) is an entity first described by Bolognia et al in 2010. It is characterised by persistent discrete discoid papulosquamous lesions with minimal dry scale and facial predilection. These lesions are treatment resistant and have histological features of PRP. It has been proposed that FDD is a previously unrecognised type of PRP (i.e. Type VII PRP). In a case series by Gan et al, one of the eight patients with FDD who developed full-blown Type II PRP further supports this postulation. Although further stud- ies are required to determine if FDD is a PRP variant or a separate entity, recognition of its distinctive clinicopatholog- ical features will hopefully decrease the number of patients who currently lack a diagnosis for their persistent facial lesions.