Unlike most non-Hodgkin lymphomas (which are generally B-cell-related), CTCL is caused by a mutation of T cells.

These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.

[1] The cause of CTCL remains largely unknown, but several external risk factors have been proposed as potential triggers and promoters of the disease.

These include the use of hydrochlorothiazide diuretics, therapy-induced immunosuppression, and possible infections by a range of viral (e.g., HTLV-1, HTLV-2, HIV, Epstein-Barr virus, Cytomegalovirus, HHV-6, HHV-7, HHV-8 (KSHV), and Polyomaviruses such as Merkel cell polyomavirus) and bacterial or fungal pathogens (including Staphylococcus aureus, Mycobacterium leprae, Chlamydophila pneumoniae, and dermatophytes).

FDA approved treatments include the following:[10] Histone deacetylase (HDAC) inhibitors are shown to have antiproliferative and cytotoxic properties against CTCL.