Prurigo pigmentosa: a clinical and histopathological study of nine Chinese cases

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.

Skin diseases in Asian individuals that you do not want to miss: A selection of unique or relatively more common conditions in Asian populations

The Asian population currently constitutes a simple majority of the global population, comprising nearly 60%. The percentage of the US population that identifies as Asian is expected to grow to 41 million by the year 2050, making up an eventual 9% of the US population. As the world and US populations of Asian individuals increase, the demand for dermatologic care from this population will increase, requiring dermatologists to become more familiar with the diagnosis and treatment of Asian-specific skin characteristics and diseases. In this contribution, we review skin conditions specific to or relatively more common in Asian patients to help recognition and management of diseases in an increasing Asian patient population. We discuss prurigo pigmentosa, primary cutaneous plasmacytosis, lipodystrophia centrifugalis abdominalis infantilis, Epstein-Barr viru-positive T- and natural killer-cell lymphoproliferative disorders, acquired bilateral nevus of Ota-like macules, and Behҫet disease.

Bullous Prurigo Pigmentosa

Prurigo pigmentosa (PP) is an inflammatory dermatosis with unknown etiology. The clinical presentations of PP varies according to the stages of the disease. Rarely, the formation of numerous vesicles and bullae upon erythematous infiltrative plaques can be found during the entire clinical course. In the present case, a 29-year-old Chinese woman presented with a 6-year history of relapsing pruritic erythematous plaques and bulla on her neck, chest and back. Physical examination revealed multiple erythematous plaques and vesicles in combination with mottled pigmentation in a symmetrical distribution and reticular pattern on the nape of her neck, chest and back. Histological examination of the biopsy specimen collected from the bullous area of her chest indicated a lichenoid reaction with intraepidermal bulla. This inflammatory region is characterized by recruitment of lymphocytes, spongiosis, and a perivascular lymphohistiocytic infiltrate in the upper dermis. Direct immunofluorescence analysis for IgG, IgA, IgM and C3 was negative. The diagnosis of bullous prurigo pigmentosa was verified based on the clinical manifestation and pathological findings. Minocycline hydrochloride therapy (100mg/d) was initiated, and 3 weeks later the rash had completely disappeared, which resulted in pigmentation of the entire area. No recurrence was observed during the 4 years follow-up.

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

INTRODUCTION

Prurigo pigmentosa is a rare inflammatory, pruriginous skin disease seen predominantly in young Asian women, with average age of onset in the mid-20s.

OBSERVATION

A 25-year-old fair-skinned European woman presented with a two-year history of pruriginous skin lesions recurring fortnightly. The initial lesions were inflammatory papules, which first emerged on the back of the neck before spreading to the shoulders, below the breasts and the back. The papules resolved leaving a reticular hyperpigmented network that gradually worsened after each episode. The clinical presentation and histopathological findings were consistent with a diagnosis of prurigo pigmentosa. Doxycycline 200mg/day was initiated, with rapid resolution, absence of any further flare-ups and gradual regression of the reticular pigmentation.

DISCUSSION

Prurigo pigmentosa is a skin disease of stereotypical presentation marked by frequent inflammatory flare-ups involving the trunk that are followed by periods of remission with residual hyperpigmentation. Herein we report a case observed in a fair-skinned French female subject. It is important that dermatologists are able to recognize it and distinguish it from other forms of pruriginous papular dermatosis, owing to the dramatic efficacy of tetracyclines in controlling the inflammatory flares and in reducing the adverse aesthetic impact of hyperpigmentation.

[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.