Prurigo Pigmentosa Successfully Treated with Low-Dose Isotretinoin

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

Die Prurigo pigmentosa ist eine schubweise an Brust, Rücken oder Nacken auftretende Dermatose mit juckenden, erythematösen, meist retikulär angeordneten Papeln unklarer Ätiologie. Frauen sind häufiger betroffen als Männer. Topische Therapien sind meist wenig zielführend. Orale Systemtherapien sowie im Einzelfall auch diätische Maßnahmen können eine anhaltende Besserung bringen. Wir beschreiben hier den Fall einer 25-jährigen europäischen Patientin, welche erfolgreich mit Minocyclin per os behandelt wurde.

A Review of Oral Therapies for the Treatment of Skin Hyperpigmentation

This review article examines evidence supporting the use of oral therapies in treating idiopathic, actinic, and metabolically induced skin hyperpigmentation. A thorough review of the literature regarding oral treatments for hyperpigmentation was systematically conducted through PubMed. Keywords used in the primary search include "Hyperpigmentation," "Melanosis" or "Melasma," "Lightening," "Oral," and "Therapeutics." The search was limited to the English language, and no timeframe restrictions were implemented. Numerous orally administered therapies have been proposed for the treatment of skin hyperpigmentation. There is an abundant body of literature demonstrating the efficacy of orally administered tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. It is reasonable to expect that the most effective oral therapies will address known underlying causes of hyperpigmentation such as thyroid disease, diabetes, and hormonal imbalance. Improvement due to oral therapy of otherwise unresponsive skin hyperpigmentation or hyperpigmentation of unknown cause is less predictable. This review is limited by the strength of evidence contained within the available studies. Clinical studies investigating the treatments discussed within this article are limited in number, at times lack blinding in the study design, and are based on small sample sizes. Based on existing research, the most promising oral remedies for hyperpigmentation appear to be tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. Additional studies to better establish safety and efficacy are necessary.

Low dose of isotretinoin: A comprehensive review

Isotretinoin is a first-generation retinoid initially approved for the treatment of severe cases of acne vulgaris (nodulocystic acne). Because of its broad anti-inflammatory and immunomodulatory properties, it has been used beyond its initial approval in a myriad of other indications. Adverse effects of isotretinoin vary from xerosis to teratogenicity. Herein, we reviewed the literature, through date-unlimited PubMed search, from inception till December 2019, using the following search terms: "low-dose isotretinoin" and "dermatology," "isotretinoin and safety," "isotretinoin, off-label uses," "isotretinoin and male fertility," "isotretinoin, iPLEDGE system," aiming to deliver a therapeutic update relevant to clinical practice. All English-language articles were considered with no limitation based on the articles' type. Low-dose isotretinoin is not limited to old and novel dermatological conditions, but also showed promising results in the field of infertility and safety in the field of gastroenterology. We also highlight on the safety profile of the drug and experts' recommendations to enhance safety measures to decrease fetal risk while on isotretinoin.

Dermatological indications for the use of isotretinoin beyond acne

While the use of isotretinoin has revolutionized the treatment of acne vulgaris, isotretinoin is increasingly recognized as a useful therapeutic option for many other cutaneous conditions. We review the evidence underlying the use of isotretinoin for a variety of dermatological indications including hidradenitis suppurativa, sebaceous gland pathology, rosacea, scarring alopecia, cosmetic dermatology, and non-melanoma skin cancer prophylaxis amongst other uses, and thus consider alternative uses within dermatology practice. The studies found benefit of isotretinoin, however most trials lacked statistical power and in many cases the use was limited to case series. Isotretinoin, if used within the correct cohort with appropriate pretreatment counseling regarding side-effects, is a well-tolerated medication with potential as either an adjunctive treatment or a second-line agent in those recalcitrant cases unresponsive to first-line therapy.

Prurigo Pigmentosa-Report of 3 Cases From Brazil and Literature Review

Prurigo pigmentosa (PP) is a rare inflammatory disease of the skin of uncertain etiology first reported in Japan. It is typified by recurrent eruptions of itching urticarial macules, papules, vesicopapules, and plaques with a reticular arrangement that quickly resolve leaving a net-like pigmentation. The disease presents specific histopathological features. Herein, 3 cases of PP in Brazilians with no Japanese ancestry are reported and a revision of all previous English-language case reports indexed on PubMed is provided. Two articles with original case reports not listed on PubMed were also included. Our patients are 2 women and 1 man at the ages of 39, 33, and 22 years, respectively. All 3 presented findings in consonance with previous cases of PP and were diagnosed based on clinicopathological correlation. They were successfully treated with oral minocycline or doxycycline. In our literature review, a total of 210 previously reported cases were included. Although PP seemed to be restricted to Japanese patients in the first years after its recognition, the geographic boundaries of the disease are continuously expanding. Korea responded for 83 previous cases and Japan for 53. The mean age was 24.4 years, with 84.3% of the cases occurring between 11 and 30 years of age. The female/male rate was 2.6 and the most affected anatomical sites were back, chest, and neck. We do believe that the rarity of case reports in western countries may represent lack of awareness about the disease by dermatologists and dermatopathologists in these regions.

Prurigo Pigmentosa: Literature Review

Prurigo pigmentosa, also referred to as Nagashima's disease, is a rare inflammatory skin condition of unknown etiology. It typically presents as pruritic erythematous papules, papulovesicles, and vesicles appearing in a reticular pattern on the back, chest, or neck. The histological features of prurigo pigmentosa vary according to the stage of the disease. Early-stage disease is characterized by a superficial perivascular infiltrate of neutrophils; spongiosis and necrotic keratinocytes commonly appear in later stages. The etiology of prurigo pigmentosa has yet to be determined. Oral minocycline is usually the first-line therapy for prurigo pigmentosa. However, doxycycline, macrolide antibiotics, and/or dapsone (diaminodiphenyl sulfone) may be indicated for some patients. We describe the key features of prurigo pigmentosa, including the epidemiology, clinical and histologic presentation, differential diagnosis, postulated pathogenesis, and treatment options for this condition.

Identification of Helicobacter pylori in skin biopsy of prurigo pigmentosa

A 23-year-old Chinese man presented with a 3-year history of a pruritic eruption. On examination, pink urticarial papules associated with hyperpigmented reticulated patches were noted on his neck, back, and upper chest. Histopathology revealed vacuolar interface dermatitis and numerous gram-negative rods within a dilated hair follicle. The organisms were reactive with anti-Helicobacter pylori immunohistochemisty. The histologic findings and clinical presentation support the diagnosis of prurigo pigmentosa. Additional testing demonstrated a positive urease breath test and serum H. pylori IgG antibodies. The patient was referred to gastroenterology and treated with appropriate antibiotics. After treatment, esophagogastroduodenoscopy revealed chronic gastritis without evidence of H. pylori infection and his skin showed reticulated hyperpigmented patches without evidence of active inflammatory papules. Although previous reports have associated prurigo pigmentosa to H. Pylori gastritis, this is the first report of H. pylori organisms identified in a skin biopsy of prurigo pigmentosa.