(( the meeting
(( the course
(( key dates
(( basic facts
(( contact us
When to suspect a photoallergic reaction?
Photobiology Unit, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK
Photoallergic contact dermatitis is thought to occur when an exogenous agent combines with a carrier molecule within the skin in the presence of light, to create an antigenic complex. Currently, the best method of investigating photoallergy in humans is photopatch testing. Sunscreens and topical nonsteroidal anti-inflammatory drugs (NSAIDs) are currently the commonest photoallergens.
Indications for photopatch testing include:
Patients should be aware that there are benefits and disadvantages to having photopatch tests performed and it is their choice on whether to proceed with the investigation.
To perform photopatch testing, the clinician should have as a minimum, a radiation source, test agent(s) and a method of recording results. Due to the multiple steps involved in photopatch testing, there have been differing methodologies over recent years. However, a European consensus methodology now exists to allow better comparison between centres. For photopatch testing photosensitive patients, a dose 50% that of the UVA MED or the dose below the MED has been suggested.
Bruynzeel DP, Ferguson J, Andersen K et al. Photopatch testing: a consensus methodology for Europe. J Eur Acad Dermatol Venereol 2004; 18: 679-682.
© Alastair Kerr (text) and Radoslaw Spiewak (source code).
This page is part of the website photopatch.eu (contact).
Document created: 30 August 2009, last updated: 7 September 2009.