Medical Q&As

Eczema - patch testing?

My son has had eczema since he was born 2 years ago. My doctor has suggested “patch” testing. What does this involve and where can I get it done.

Some GPs have a special interest in allergy testing and your GP could refer you to one of those doctors if he or she was unable to do the testing for you. Alternatively your GP could refer you to see a specialist for further testing. The patch test involves applying several common allergens to the skin. These are usually applied in batches to the skin on the child’s back. The skin is then inspected within a few days to detect if any reaction has occurred in the child’s skin. If the child is allergic to any of the allergens an area of inflammation develops at the point where the particular allergen was applied. Once the allergen has been identified it may then be possible to avoid the child being exposed to that agent in the future, which should help to prevent further relapses of eczema. The theory behind patch testing is very sound but in practice it is often discovered that the child has multiple allergies to very common ubiquitous agents that cannot be easily avoided.