Eosinophilic dermatosis of haematological malignancy: a 24-year review

Eosinophilic dermatosis of haematological malignancy (EDHM) is an uncommon paraneoplastic eruption predominantly affecting patients with chronic lymphocytic leukaemia (CLL), though it may be associated with other haematological malignancies. Its clinical and histopathological features often mimic other dermatoses, complicating diagnoses and delaying treatment. The objective of this study was to characterise the clinical and histopathological spectrum of EDHM in a cohort of patients. A retrospective review of skin biopsies reported between January 2000 and January 2024 was conducted at a tertiary referral centre. Cases with histological features suggestive of EDHM and a confirmed diagnosis of haematological malignancy were included. Clinical and histological data were extracted from medical records and pathology reports. A total of 16 biopsies from seven patients were reviewed. CLL was the most common underlying malignancy (n=3, 43%), followed by diffuse large B-cell lymphoma, follicular lymphoma and paraproteinaemia. Cutaneous lesions were polymorphic, most commonly vesiculobullous or papular, and predominantly affected the limbs. Histologically, all specimens showed superficial perivascular inflammation. There was mixed inflammatory infiltrate, with 35% exhibiting a dense eosinophilic infiltrate, and 25% of specimens exhibited vascular changes. No flame figures or evidence of leukaemia cutis was identified. Most patients improved with topical corticosteroids, while systemic corticosteroids and dapsone were used in select cases. Recurrence was uncommon. EDHM presents with diverse clinical and histological features, often clinically and histologically resembling arthropod bite reactions. A high index of suspicion is required in patients with haematological malignancy presenting with pruritic eruptions. Corticosteroid therapy is generally effective, though further studies are needed to clarify optimal management and long-term outcomes.