Light urticaria

Last Updated: 2023-07-07

Author(s): Anzengruber F., Navarini A.

ICD11: -

Merklen 1904

Urticaria solaris, solar urticaria, photoallergic urticaria, solar urticaria

A form of urticaria that can be triggered by UV radiation (from infrared to UVC)


UV radiation (from short-wave IR to long-wave UVC rays) is the trigger. Almost all patients react to visible light. A precursor of the allergen (chromophore) absorbs incident UV radiation and becomes the photoallergen. Specific IgE causes histamine release and the development of urticaria.


Urticaria in the area of UV-exposed sites. In rare cases, Quincke's oedema and an anaphylactic reaction may occur.


Clinical picture

Photoprovocation testing (UVA, -B, -C, IR, visible light) with determination of minimum urticaria dose (MUD)

Anaphylactic reactions have been described in case of whole body exposure.

UV protection