LEEP asked what shampoos and conditioners would be good to use for allergic responses. This is a question you may want to ask your dermatologist. If you do a skin allergy test before applying Ecocolors Haircolor to your entire head, you will minimize the risk of having an allergic response. Some physicians have recommended using an antihistamine like benadryl for an allergic response. Ecocolors does not recommend that you use EcoColors Haircolor if you show any redness or irritation after your allergy patch test(done according to manufacturers directions).