Atopic dermatitis (AD) and spontaneous chronic urticaria (SCU) are two chronic inflammatory skin diseases with a high impact on quality of life. Failure of conventional therapies -聽topical steroids in AD and anti-histamines in SCU聽- is not rare. This could lead to treatment with immunosuppressive drugs, but the mode of action of such drugs is not specific for the pathophysiology of these diseases, and their use is not without undesirable side effects. The therapeutic revolution which we have seen with the advent of biological therapies for psoriasis has brought new hope for the development of other drugs aimed more at the pathophysiology of AD and CSU.