A systemic version of miltefosine is being investigated in Phase II trials for severe antihistamine-resistant urticaria.

Miltefosine works by targeting lipid rafts that regulate mast cell and T-cell activation. It intervenes in the upstream steps of the immune cascade, whereas current drugs, antihistamines and steroids, target more downstream events. This novel mode-of-action for miltefosine offers clear advantages over existing drugs.