Prurigo pigmentosa as an atypical persistent plaque-like skin rash in adult-onset Still’s disease: case report and literature review

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.

Clinical manifestations and treatment outcomes in prurigo pigmentosa (Nagashima disease): A systematic review of the literature

BACKGROUND

Prurigo pigmentosa (PP) is a rare inflammatory dermatosis characterized by pruritic erythematous papules that coalesce to form a reticulate pattern. PP is often misdiagnosed, and patients are treated with ineffective therapies. Although the majority of reports about PP are from East Asia, patients of all backgrounds can be affected.

OBJECTIVES

To perform a systematic review of reported PP cases with the purpose of summarizing the clinical presentation and treatment of PP.

METHODS

MEDLINE and Embase were searched for original articles describing PP. We identified 115 studies from 24 countries representing 369 patients to include in the analysis.

RESULTS

Of the 369 patients included in the analysis, the mean age was 25.6 years (range: 13-72 years) with 72.1% (266 of 369) female. Risk factors or aggravating factors were described in 52.3% (193 of 369) of patients and included dietary changes (25.5%, 94 of 369), friction (8.4%, 31 of 369), sweat (7.6%, 28 of 369), and ketonuria (5.1%, 19 of 369). Of those patients who experienced PP following dietary changes, 40.4% (38 of 94) started a ketogenic diet. Minocycline monotherapy was the most frequently prescribed treatment for PP (20.9%, 77 of 369), achieving complete resolution in 48.1% (37 of 77) of patients.

CONCLUSIONS

PP is sometimes associated with ketogenic diets and can be effectively managed with oral tetracyclines.

Prurigo pigmentosa

Wir berichten über eine in Europa selten auftretende Erkrankung. In unserem Fall erkrankte ein 28-jähriger sonst gesunder Mann an Prurigo pigmentosa (PP). Die Diagnose wurde erst 6 Jahre später anhand der klinisch pathologischen Korrelation gestellt. Die Ätiopathogenese in unserem Fall ist unklar. Wir behandelten mit Minozyklin. Hierunter kam es zu einer raschen Befundbesserung.

Typisch für die PP ist der mit dem Auftreten der Hautveränderungen beginnende starke Juckreiz, die retikuläre Anordnung sowie der im Frühjahr und Sommer schubweise Verlauf. Aufgrund des in Europa seltenen Auftretens werden, wie auch in unserem Fall, zunächst Differenzialdiagnosen wie z. B. eine kontaktallergische Dermatitis in Betracht gezogen. Wahrscheinlich ist die Inzidenz von PP in Europa deutlich höher, sie bleibt nur oft unerkannt.

Adult-onset Still's disease as a cutaneous marker of systemic disease

Adult-onset Still's disease (AOSD) is a rare, systemic, inflammatory disorder characterized by spiking fevers, an evanescent eruption, arthritis, and multiorgan involvement. The disease has been recently classified as a polygenic autoinflammatory disorder at the "crossroads" of autoinflammatory and autoimmune diseases. The highly characteristic salmon-colored eruption is a cutaneous manifestation of a generalized inflammatory reaction and an important diagnostic criterion. In addition to the evanescent eruption, there are atypical persistent papules and plaques in many patients with AOSD. Emerging data suggest that AOSD with this typical evanescent eruption has a different clinicopathologic presentation and clinical course than AODS with atypical cutaneous manifestations. It appears that there are two subtypes of AOSD with different immunologic profiles, including (1) a systemic disease with high fever, organ involvement, and elevated levels of ferritin, and (2) a chronic disease course with arthritis as the predominant finding. These observations provide novel insight into the disease pathogenesis, suggesting that the underlying mechanisms might differ between these two forms, partially explaining the reported differences in drug response. Recent advances in the understanding of AOSD are summarized with a focus on the spectrum of cutaneous manifestations and its relationship to systemic inflammation.