Clinical Features and Follow-Up of Prurigo Pigmentosa: A Case Series

Introduction Prurigo pigmentosa (PP) is an underrecognized disease in the Western population. Our aim is to describe the clinical features and follow-up outcomes of Caucasian patients diagnosed with PP. Methods This case series was conducted in the dermatology outpatient clinic of a tertiary hospital. Patients with confirmed PP from May 2020 to June 2021 were included in the study. Patient demographics, clinical features, potential triggers, treatment and follow-up data were recorded. Results A total of eight patients with female predominance were identified. The mean age of the patients was 24.5. The duration of symptoms ranged from four days to six months. All patients presented with pruritic, papular or papulovesicular lesions. Net-like hyperpigmentation was also present at the initial visit in two patients, in whom the duration of the symptoms was the longest. Lesions were most commonly located on the chest and back. Six of eight patients reported alteration of diet that potentially led to ketosis. Doxycycline 200 mg daily for two weeks led to a complete response in all six medically treated patients. Duration of follow-up ranged from 1-14 months (mean: 7.2 months). In five patients with a follow-up duration of more than three months, postinflammatory hyperpigmentation was resolved without any treatment. Only one patient had a recurrence. Conclusion PP does not seem to be a rare disease. Young women are most commonly affected, and ketosis stemming from decreased calorie intake may be the etiological factor in the majority of the patients. Dermatologists should be familiar with early signs of PP in order to minimize unnecessary therapies, recurrences and long-lasting hyperpigmentation.