Antihistamines may sometimes be used to help relieve troublesome itching in people with psoriasis, particularly if itching is affecting sleep. Antihistamines work by blocking the action of histamine at H1 receptors, reducing the effects of histamine in the body.
In psoriasis:
- itch is caused by a complex interaction of inflammatory cytokines, nerve fibres and immune cells
- histamine does not appear to be the main driver
- this is why antihistamines often have limited benefit for psoriasis itch
In allergic conditions, blocking the action of histamine can reduce itching. In psoriasis, however, itching is caused by several different mechanisms, so antihistamines may not relieve itching for everyone. Sedating antihistamines may help some people sleep better if itching is disturbing their rest. Scratching can damage the skin and may trigger new psoriasis plaques to develop in susceptible areas (known as the Koebner phenomenon). It can also increase the risk of secondary skin infection. Persistent itching can affect sleep, concentration, mood and quality of life.
They are not a treatment for psoriasis itself.
Non-sedating antihistamines are less likely to cause drowsiness.
Sedating antihistamines may affect driving or operating machinery.
They should be used according to the advice of a healthcare professional or the patient information leaflet.
Reviewed: August 2026
Version ID: 2/ANT/PST/08/26
