Papuloerythroderma

1 - DEFINITION AND DIAGNOSIS

First described in 1984, papuloerythroderma (of Ofuji) is defined by a set of clinical, biological and histological signs. The first cases were described in Japan, but instances elsewhere, primarily in Europe, have since been reported. Nonetheless, papuloerythroderma remains a rare disorder (about 170 cases have been reported) and its existence as a separate entity and its relationship with skin T-cell lymphomas are controversial.

The disorder is mainly observed in subjects aged over 55 and affects more men than women (4/0 sex ratio). Typically, the papular, reddish-brown, extremely itchy lesions are located on the limbs and trunk. The deep parts of the major skin folds (inguinal, axillae, etc.) are spared as are the abdominal and dorsal folds, creating the distinctive so-called deck-chair sign. The eruption develops over a matter of months until the papules eventually coalesce to form a widespread rash, but it very rarely looks like erythroderma in the strictest sense of the term. It is a chronic condition. The face is often spared. Palmoplantar keratoderma, sometimes with fissures, is rarer (about 1/3 of cases). One in two patients present with polyadenopathies. Patients are apyretic and any constitutional syndrome present is generally caused by the chronic, conventional treatment-refractory itching which may prevent the sufferer from sleeping.

The most typical abnormal laboratory test result is eosinophilia, with which over 80 percent of patients will present to varying degrees (up to 10 x 109/L; N < 0.5 x 109/L). Elevated total IgE is observed in two thirds of cases. Lymphocytopenia is not always present (40 percent of cases) and, in the elderly, is not a specific sign of the disorder.

The histological findings are not distinctive, consisting of a perivascular polymorphous infiltrate in the upper and middle dermis made up of lymphocytes, histiocytes and eosinophils. Immunohistochemistry shows the presence of Langerhans cells and abundant T CD4+ cells. In places, the epidermis may be parakeratotic or may present spongiosis, sometimes with exocytosis. No atypical cells are present.

A lymph node biopsy has the histological appearance of dermopathic lymphadenopathy.

The pathophysiological mechanism involved is as yet unknown. The predominance of T CD4+ cells and Langerhans cells in the infiltrate has led to the hypothesis that papuloerythroderma arises as a reaction to an unidentified cutaneous antigen.

2 - PSYCHOLOGICAL IMPACT AND PATIENT INFORMATION

Although the clinical picture does not strictly match that of erythroderma, the wide-spread, chronic and extremely pruritic nature of the lesions can cause depression if not treated promptly and effectively. Patients must be informed that, although it is rare, dermatologists are familiar with the condition and, in most cases, are able to control it with the treatment options at their disposal. The importance of long-term clinical monitoring must be stressed.