A report describes a case of a 55-year-old male who presented with progressively intensely pruritic erythematous papules and plaques on his trunk, upper extremities, neck and face over 8 months. Physical examination revealed partially confluent lesions with well-demarcated areas of spared skin and superficial fine scaling. Dermoscopy showed a homogeneous pink background with glomerular and irregular dotted vessels associated with fine superficial scaling. He had a medical history of gastroesophageal reflux disease, treated with esomeprazole.

His general lab tests (CBC, chemistry panel, hepatic profile) were normal, and HIV, hepatitis B, hepatitis C and VDRL serologies were all nonreactive.

Two punch skin biopsies showed suprabasal focal acantholysis with numerous dyskeratotic cells and eosinophils.

What do you suspect?

1. Pityriasis rubra pilaris (PRP)
2. Atypical Grover′s disease (GD)
3. Darier′s disease
4. Pemphigus foliaceus

Discussion

This case showed extensive facial involvement, an uncommon feature of GD. Interestingly, this patient also showed the presence of well-demarcated areas of spared skin, which could be a strong diagnostic pitfall towards PRP. However, there are case reports of PRP with histopathology compatible with GD and vice versa, suggesting an overlap between these two diseases in a cohort of patients.

The dermoscopy of this patient showed a pink background with polymorphous vessels (glomerular, dotted, lineal and hairpin) and star- or oval-shaped yellow-white structures with a white halo, besides scaling. Typically, it shows focal acantholysis and different degrees of dyskeratosis and has four histologic subtypes: Darier′s disease-like, pemphigus-like, Hailey-Hailey-like and spongiotic. These subtypes can appear independently or coexist.

First-line treatment involves emollients, topical steroids and vitamin D analogs associated with H1 antihistamines. Extensive or treatment-resistant cases utilize therapy with systemic retinoids, oral steroids or phototherapy. The present case used narrowband ultraviolet B phototherapy with a successful response after 18 sessions.

Source: Vargas-Mora P, Orlandi D, Araya I, et al. Case for diagnosis. Atypical Grovers disease. An Bras Dermatol. 2021;96(2):234-6.