When the animal licks itself, the saliva gets on the fur. As the saliva dries, protein particles become airborne and work their way into fabrics in the home. Guinea pigs and gerbils can also cause allergies, most likely due to protein in their urine. Food allergens Severity of food allergies and when they develop depends on the quantity of the food eaten, the amount of exposure the child has had, and the child's sensitivity to the food. Common foods that may cause allergies include cow's milk, soy, egg whites, wheat, shellfish, and peanuts.
Peanuts are one of the most severe food allergens, often causing life-threatening reactions.
In the test, a drop of a purified liquid form of the allergen is either dropped onto the skin and the area pinched with a small plastic device, or a small amount of allergen is injected just under the skin. This only pinches a little. After about 15 minutes, if a reddish area, like a mosquito bite, appears at the injection site, the test is positive. A child must also have symptoms for a definitive diagnosis. For example, a toddler who has a positive test for dust mites AND sneezes frequently while playing on the floor would be considered allergic to dust mites.