Idiopathic Papular Dermatitis in the Spectrum of Chronic Papular Eruptions (Subacute Prurigo): Reappraisal and...

The clinical diagnosis of papular eruptions is common but poorly characterized in the literature and the etiology is often unknown.

To characterize the entity of idiopathic papular dermatitis in the spectrum of chronic papular eruptions.

The cohort consisted of patients who presented at a tertiary medical center in 2005-2014 with a papular eruption of at least 4 months' duration. Findings on histological analysis and thorough clinical investigation, performed in all cases, were collected. The patients completed a questionnaire on disease course and outcome.

Sixty-five patients were included. Sixteen patients showed morphological changes over time and were excluded. Investigations in the remaining 49 patients with a consistent papular morphology yielded a well-defined diagnosis in 23 (46%). Twenty-six patients (54%; 14 male) were diagnosed with idiopathic papular dermatitis. Their mean age at onset was 61.6 ± 14.4 years and the mean duration of disease 3.11 ± 2.726 years. In 60%, the rash resolved with conservative treatment during follow-up (mean 4.35 ± 2.53 years).

Chronic papular eruptions encompass a wide range of skin diseases. In more than half of the cases, the etiopathogenesis remains unclear. On the basis of our results, we propose a diagnostic algorithm for idiopathic papular dermatitis.