Pruritus may cause severe chronic discomfort to PV patients. Most of t
he usual treatments are not at all or only weakly efficient. Photochem
otherapy using psoralen and ultraviolet A light may largely improve th
e clinical symptom of intractable itching, as observed in ten of the 1
1 cases presented, but maintenance therapy is generally necessary. The
treatment may then improve the patient's quality of life.