Prurigo Pigmentosa: Demographics and Characteristics in 14 Caucasian Patients

Abstract

<b><i>Background:</i></b> Prurigo pigmentosa (PP) is an inflammatory dermatosis typically reported in young Asian women and characterized by recurrent papulovesicular lesions resolving with a postinflammatory reticulated hyperpigmentation. <b><i>Methods:</i></b> We have included all consecutive patients with PP diagnosed in our tertiary center between 2013 and 2020. The clinical information was retrospectively collected from medical records. <b><i>Results:</i></b> We identified 14 patients with PP. The median age at the time of diagnosis was 29.5 years (range 17–43 years), while the female-to-male ratio was 13:1. Diagnostic delay varied from 10 days to 10 years (mean of 25 months). Light microscopy studies consistently showed presence of a lymphohistiocytic infiltrate in combination in 40% of cases with neutrophils. Interface changes were found in 60% of cases. In 6 (43%) of 14 cases, there was a chronological relationship between the starting of a new diet and the development of the first flares. Treatment with doxycycline in 9 patients resulted in a complete regression of the lesions. <b><i>Limitation:</i></b> This was a retrospective study in a tertiary referral hospital. <b><i>Conclusions:</i></b> Our observations indicate that PP is not so rare in Europe as previously thought and is often diagnosed after a long delay. Demographics, clinical characteristics and triggering factors in Caucasian patients are similar to those described in the Asian population. Diagnosis is based on the peculiar recurrent course and distinctive clinicopathological features. Tetracyclines represent the first-line therapy in PP.