Prurigo pigmentosa in a fair-skinned European woman: Dramatic improvement with doxycycline

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.

Prurigo Pigmentosa: Demographics and Characteristics in 14 Caucasian Patients

BACKGROUND

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.

METHODS

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.

RESULTS

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.

LIMITATION

This was a retrospective study in a tertiary referral hospital.

CONCLUSIONS

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.

Doxycycline, an Antibiotic or an Anti-Inflammatory Agent? The Most Common Uses in Dermatology

Doxycycline is a synthetic tetracycline that was approved in 1967. This wide-spectrum antibiotic has been shown to also have useful anti-inflammatory properties that make it suitable for the treatment of a number of noninfectious conditions. Tetracyclines are probably the most commonly prescribed antibiotics in dermatology, where they are usually used at doses lower than those effective against infections. They also have an excellent efficacy and safety profile. Because of doxycycline's ability to inhibit the molecular pathways associated with certain processes, this antibiotic can be used to treat hair follicle diseases, granulomatous diseases, and vascular proliferation, among other conditions. The main properties of doxycycline and its many applications in dermatology make this drug one that specialists should become familiar with.