Abstract
Acute graft vs host disease (AGVHD) is a multisystem disease affecting predominantly the gastrointestinal tract and the skin of immunosuppressed transplant recipients and occurs because of immunocompetent donor T-lymphocytes responding to the recipient major histocompatibility complex antigens. Classically, it presents within 100 days post-transplant. Like adverse drug reactions and viral exanthema, Demodex folliculitis is a clinical mimicker of AGVHD. We present the case of a 56-year-old man with a history of acute myeloid leukemia in remission after chemotherapy (cytarabine, anthracycline and midostaurin) and bone marrow transplantation (day +56) who is admitted with leukocytosis, hyperkalemia, diarrhea, vomiting and a new erythematous scaly dermatitis involving his face of 2 days of evolution and recalcitrant to topical steroids. Given clinical concern for AGVHD, Dermatology was consulted for recommendations. A skin biopsy was performed and revealed Demodex mites within dilated follicular ostia, focal spongiosis of the follicular epithelium and rare dyskeratotic keratinocytes in the upper levels of the epidermis. The overlying stratum corneum displayed parakeratosis which was more pronounced at the follicular orifices and an underlying mild superficial perivascular lymphocytic infiltrate. The diagnosis of Demodex folliculitis was rendered and the patient was started on Permethrin 5% cream and significant clinical improvement was noticed several hours later. Overall, our case emphasizes the importance of including Demodex folliculitis in the differential diagnosis of an erythematous dermatitis on the face of an immunosuppressed patient. It is essential to differentiate this entity from AGVHD since the latter has a poor prognosis and its management is completely different.
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