Eosinophilic dermatosis of hematologic malignancy (EDHM) is a rare dermatosis associated with blood tumours.

To characterize the expression of T-, B-cell markers and pruritogenic mediators in EDHM skin.

Immunohistochemical and immunofluorescence analysis were performed in 12 skin samples of EDHM, 11 samples of bullous pemphigoid (BP) and 5 samples from healthy controls (HC). Serum levels of IL-4 were analyzed in 11 EDHM patients, 11 BP patients and 5 HC by enzyme-linked immunosorbent assay.

T-cell markers, including CD3, CD4, CD8 and CD5 were significantly over-expressed in EDHM, and BP skin compared to HC. A predominance of CD4+ over CD8+ cells and GATA3+ (Th2 marker) over T-bet+ (Th1 marker) cells were observed. FOXP3 expression was increased but there was a low FOXP3/CD4 ratio. B-cell markers were under-represented, without significant differences between the three groups. IL-4 and IL-31 were significantly over-expressed in EDHM and BP compared to HC and co-localized with the Th2-associated marker GATA3. Eotaxin-1 was significantly over-expressed in EDHM compared to BP and HC. IL-4 serum concentration was significantly increased in EDHM and BP compared to HC.

Small sample size; retrospective design.

Targeting Th2-related molecules, in particular IL-4, holds promise for EDHM management.