BG04 (P003) Papuloerythroderma of Ofuji-like eruption: unfolding a distinctive reactive pattern

A 79-year-old man undergoing investigation for persistent leucocytosis and unintentional weight loss was referred with a 3-month history of an intensely pruritic rash. Examination revealed an extensive eruption of erythematous–brown papules and pustules that coalesced into confluent areas, with sparing of the inframammary region. Initial investigations included a leucocytosis of 18.2 × 109 cells L−1, with a peripheral eosinophilia of 5.8 × 109 cells L−1. Skin biopsies from his limbs exhibited parakeratosis, spongiosis, neutrophil aggregates in the stratum corneum, and upper-dermal perivascular chronic inflammation with abundant eosinophils extending into the overlying epidermis. An underlying lymphoproliferative disorder was suspected, but a bone marrow aspirate did not support this, instead exhibiting a striking increase in eosinophils with a normal spectrum of maturation. Further investigations, including liver biopsy, revealed a metastatic adenocarcinoma of colorectal origin. Telmisartan, the only recently initiated medication, was commenced 3 months prior to the onset of the rash but discontinued after 4 weeks due to pruritus. The initial working diagnosis was that of a paraneoplastic rash. The patient was initiated on topical fusidic acid/betamethasone and clobetasol, and received intravenous 5-fluorouracil chemotherapy. After 3 months, the rash remained recalcitrant. Subsequent oral prednisolone yielded partial benefit, with improvement in itch but persistent rash. Further reflection on the clinicopathological features led to a diagnosis of papuloerythroderma of Ofuji (PEO)-like eruption with pustules. The patient was initiated on acitretin and referred for urgent phototherapy (acitretin–ultraviolet B) and is currently being observed for response. PEO is an eosinophilic dermatosis most commonly observed in male patients, and in those aged above 55 years (Desai K, Miteva M, Romanelli P et al. Papuloerythroderma of Ofuji. Clin Dermatol 2021; 39: 248–55). The pathogenesis is unknown, but associations with malignancy and drugs are documented. Features include peripheral eosinophilia and an eosinophilic infiltrate on histology (Desai et al.). A notable clinical feature is sparing of skinfolds; this feature was not initially appreciated in our patient, being relatively subtle due to his emaciated state. PEO-like eruptions with neutrophilic pustules have been previously reported (Maekawa A, Nakagawa Y, Kakuda K et al. A case of eosinophilic pustular follicu