Diagnosis of a dander allergy requires a physician to take a complete medical history, including a list of symptoms. A physical examination will also be performed.

If the physician suspects an allergy, a skin test or blood test will be performed. During skin testing, a physician will prick or inject an extract of an allergen into a patient’s skin and wait 10 to 20 minutes to see if there is a reaction. The development of a small, raised, reddish area generally indicates a positive reaction.

Skin testing is not practical for those with certain skin conditions. In such cases, a blood test such as a radioallergosorbent test (RAST) may be used to pinpoint the allergen causing a reaction. In this process, a patient’s blood is checked for an increase of the IgE antibody to a particular allergen, which indicates a potential allergy.