The Role of Radioallergosorbent Testing (RAST) Early in the Management of Atopic Dermatitis in Children and Adults Referred to Secondary Care in the United Kingdom

Aim: To evaluate the importance and relevance of doing radioallegrosorbent testing (RAST) for patients referred withatopic dermatitis (AD) to secondary care for specialist dermatological advice and investigation.Background: Atopic dermatitis is usually diagnosed by Primary Care General Practitioners and treated using astepped approach. Referral to secondary care is considered when it is not controlled with optimal treatment or if anallergy is suspected. Radioallegrosorbent testing is useful for identifying trigger factors however current literaturelacks evidence for the extent to which RAST testing can improve patient symptoms.Method: Standard RAST testing was requested for all patients referred to secondary care with atopic dermatitis.Allergens tested included: dairy products, house dust mite, grass, nuts, seafood, cereals, dog dander and cat epithelium.Results: RAST results showed that 92.3% of children and 60.7% of adults had high total lgE levels. The proportion ofchildren with high serum specific lgE for the allergens tested were as follows: house dust mite (60.4%), grass (50%),dairy/cow’s milk (39.5%), nuts (29.1%), dog dander (16.6%), cat epithelium (12.5%), egg (10.4%), fish/seafood(6.2%), wheat (6.2%), and soya (2.0%). The results for the adults tested were as follows: house dust mite (64.7%),grass (58.8%), cat epithelium (29%), dog dander (23%), nuts (11.7%), egg (11.7%), cow’s milk/dairy (5.8%), wheat/soya (0%). On follow-up, all patients reported an improvement in their AD after implementing allergen avoidancestrategies.Conclusions: RAST testing is a valuable clinical test that should be considered early to investigate patients with ADfor relevant allergens that may be exacerbating their symptoms and causing resistance to first line treatment.