Author: Dr Peggy Chen, Dermatology Registrar, Middlemore Hospital, Auckland, New Zealand, July 2014.
Eosinophilic dermatosis of hematologic or haematological malignancy (blood cancer) is a rare skin eruption seen in patients with underlying haematological malignancy. It was first termed as exaggerated arthropod bite lesions, as the clinical and histological features resemble arthropod bites, with prominent eosinophilia (increased numbers of eosinophils).
An eosinophil is a type of white blood cell produced by bone marrow. It is characterised by coarse granules within the cell's cytoplasm. The functions of eosinophils include:
People with underlying haematological malignancies, in particular, chronic lymphocytic leukaemia (CLL). Less commonly, the condition has been documented in patients with acute myelocytic leukaemia, acute lymphocytic leukaemia, mantle cell lymphoma and multiple myeloma.
The skin eruption may happen at the same time, before, or after the diagnosis of the underlying haematological malignancy.
The diagnosis of eosinophilic dermatosis of haematological malignancy is made by the following features:
The exact cause of eosinophilic dermatosis of haematological malignancy is poorly understood. One proposed theory is that the underlying cancer causes immune dysregulation. This leads to an imbalance in the production of cytokines (messenger proteins), with an increased production of interleukin-5 (IL-5). IL-5 recruits eosinophils into the skin.
The diagnosis of eosinophlic dermatosis of haematological malignancy is based on the following diagnostic criteria:
A variety of treatments have been used to treat eosinophilic dermatosis of haematological malignancy, but they have been reported to be largely disappointing. They include:
It remains unclear whether eosinophilic dermatosis of haematologic malignancy may have prognostic implication. Some studies have suggested that patients with eosinophilic dermatosis of haematological malignancy do poorly compared to those patients with same haematological malignancy but without the skin condition.
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