Is prurigo pigmentosa an inflammatory version of confluent and reticulated papillomatosis?

Dermoscopy and reflection confocal microscope features of pigmented prurigo

BACKGROUND

Pigmented prurigo (PP) is a chronic and recurrent inflammatory skin disease. PP is not common clinically, but it is easily misdiagnosed because of its diversified clinical manifestations in different stages.

MATERIALS AND METHODS

We retrospectively analyzed the clinical, histopathological, dermoscopy, and reflectance confocal microscopy (RCM) features of 20 patients diagnosed as PP.

RESULTS

The female predominance ratio was revealed with male to female of 1:4. Seven female patients were on a diet (without staple food) and one patient had a history of diabetes. Eight cases were suffered in spring, six cases in winter, three cases in summer, and three cases in autumn. Multiple sites were involved in 13 cases. Four patients had urticarial papules and plaques. Nineteen patients had erythematous papules with reticular distribution, of which 14 cases accompanied reticulate hyperpigmentation, four cases with papulovesicle, and two cases accompanied with pustules. One patient only showed reticulate hyperpigmentation. In the early lesions, dermatoscopy showed pink oval lesions, punctate or linear vessels, and pale yellow rings around the skin lesions. RCM is characterized by spongiosis, spongy vesicle, neutrophils scattered in the epidermis, which was consistent with epidermis spongiosis, neutrophils infiltrating into the upper epidermis and necrotic keratinocytes in histopathology. In the fully developed lesions, dermatoscopy showed pink lesions with brown pigment granules in the center and linear vessels in the edge. RCM showed that demarcation of epidermis and dermis is not clear, and inflammatory cells can be seen in the upper dermis and histopathologically lesions assumed a patchy lichenoid pattern, and the inflammatory cells infiltrating the dermis were dominated by lymphocytes. In the late lesions, dermatoscopy showed grainy grayish-brown or yellowish-brown pigmentation surrounding the hair follicle merging with each other. RCM showed that pigment granules were increased on the ring of basal cells, inflammatory cells were sparsely infiltrated in the dermal papilla and superficial layer, and epidermis slightly hyperplastic, with melanophages and a few lymphocytes infiltrating the superficial dermis in histopathology.

CONCLUSION

PP is easily misdiagnosed and not always occurs in those on a restrictive diet. A combination of dermatoscopy and RCM is helpful for its diagnosis of PP.

[Prurigo pigmentosa during pregnancy]

INTRODUCTION

Prurigo pigmentosa is a rare inflammatory dermatosis characterized by pruritic and reticulate papules on the trunk leaving hyperpigmentation. This dermatosis has been rarely described outside Asia. The pathophysiology remains obscure.

CASE REPORT

We report the case of a 21-year-old North-African woman presenting with a highly pruritic eruption with numerous erythematous macules and papules coalescing in a reticular pattern on the trunk. The eruption occurred during the first trimester of pregnancy, which was marked by severe vomiting resulting in weight loss of 13kg with ketonemia and ketonuria. Taking into account the characteristic pattern of the eruption, the absence of differential diagnosis, and the histological examination, we concluded on a diagnosis of prurigo pigmentosa. Progression of the disease exhibited phases of decreased inflammation and of pruritus alternating with episodes of inflammatory flares triggered by relapses of ketonemia. The symptoms finally resolved during the 2nd trimester of pregnancy after vomiting ceased. Secondary reticulated hyperpigmentation was observed.

CONCLUSION

Although rare, the highly evocative clinical presentation of the eruption should help clinicians in diagnosing prurigo pigmentosa. While pathophysiology remains undetermined, prurigo pigmentosa was reported in cases of intense fasting, anorexia, type-1 diabetes, and in two other cases of pregnancy with severe vomiting. Our case underlines the need to screen for and treat underlying ketonemia to achieve control of the inflammatory flares of prurigo pigmentosa.

Prurigo Pigmentosa: A Clinicopathological Report of Three Middle Eastern Patients

Prurigo pigmentosa is a unique cutaneous inflammatory disorder characterized by a sudden onset of pruritic and erythematous macules, urticarial papules, and plaques that may coalesce to form a reticulated pattern. Lesions typically heal within weeks leaving a reticulated and mottled postinflammatory hyperpigmentation. The majority of reported cases originate from Japan with much fewer cases described worldwide without predominant ethnicity. The histopathological features of prurigo pigmentosa can be nonspecific; however, distinct features exist for each stage of the disease. The aetiology of prurigo pigmentosa is not fully understood. However, ketoacidosis has been implicated in the pathogenesis and indeed prurigo pigmentosa has been associated with ketoacidotic states such as diabetes mellitus, fasting, dieting, and anorexia nervosa. In this report, we present 3 Jordanian patients with prurigo pigmentosa and describe their clinicopathological features. One patient developed prurigo pigmentosa while fasting during the month of Ramadan and another was undertaking a strict diet. No associations were identified in the third patient. In view of the largely nonspecific clinical and histological features, a high index of suspicion is required as many cases of prurigo pigmentosa are probably undiagnosed.

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.