I’ve already posted about how we tried to identify some of Grace’s food allergies by keeping a food diary. Confirming our suspicions through allergy tests was the next step. It took a couple of visits to our GP to get a referral to the local allergy clinic, but the evidence we had collected in Grace’s food diary helped to convince him that food allergies were likely. The most common method of testing for allergies is via Skin Prick Tests (SPT). Allergy UK has a useful guide to these tests, but we thought we’d share our personal experiences.
The first thing to mention is that our allergy clinic did not have samples of all of the foods we thought Grace may be allergic to. They had solutions of milk and soya and other common allergens such as cat dander, but not of less common ones like potato. Nevertheless, on our first visit we were able to confirm some of the main suspects. The testing was carried out on Grace’s back, and began with the nurse drawing a grid on her skin (in biro!). A drop of each allergen was placed in the grid squares and a small needle prick was made to allow it to penetrate.
If there is a reaction, it usually takes the form of a “wheal”, a bit like the spots of a nettle rash. These are then measured to see how severe the allergy is. Grace had the strongest reactions to egg and cow’s milk, with lesser reactions to cat dander and soya. The process was over in half an hour, and while it upset Grace it did not appear too painful. The wheals disappeared within a couple of hours – it took longer to wash the biro off!
The testing was extremely useful as it confirmed our suspicions and from them on we completely avoided the foods she had reacted to. On the second visit we took mashed samples of potato and tomato (both cooked and raw) so that they could be put in a solution and tested. This visit was more successful than the first as we found out that she was not allergic to tomatoes and we could reintroduce them into her diet. On our next visit we will ask for repeat tests of egg, milk and soya to see if her response to them has changed over time.
As a footnote, our research into nightshade allergies (the group of plants that include potatoes, tomatoes and peppers) turned up a couple of interesting things. The first is that Masterchef’s John Torode suffered from severe eczema as a child and his condition improved when he cut out the nightshade family. Given his job this gives up hope that Grace’s diet will not always be so restricted. The second is the brilliantly named “Tomatoes are Evil” website – I’m not sure how accurate their facts are, but it did make us laugh!