For recurrent or chronic atopic dermatitis, skin testing may be helpful in discovering allergic triggers of the rash. In most cases, the allergist will look for highly allergenic foods such as milk, eggs, soy, wheat, peanuts or nuts, although many other foods and inhalant allergens may be involved. Patients can also be helpful in tracking down the cause by keeping a food diary. This detective work sometimes is very helpful in establishing an important cause and effect relationship. In certain cases, blood testing (RAST or ImmunoCAP) may be helpful. This form of testing may be preferable if one’s skin rash is too inflamed to perform skin tests, or if the patient is unable to discontinue antihistamine usage five days prior to skin testing. In the case of food allergies, allergy testing may provide useful information about when the food might be safely reintroduced into the diet.