Your doctor will ask you about your symptoms, especially about when you have them and whether they occur outdoors or indoors. Your doctor also will ask about your family history of allergies and your personal history of allergy-related conditions, including eczema, hives and asthma.
Your doctor will make the diagnosis of hay fever based on your allergy history, the timing and appearance of your symptoms and the results of your physical examination. During your physical examination, your doctor will check for signs of inflammation in your eyes, nose and throat. Typically, the lining of the nose is swollen and pale pink or bluish, though it can be red. The doctor often looks for other signs of allergic rhinitis, such as dark circles under the eyes (called allergic shiners), resulting from chronic sinus congestion, wrinkles under the eyes as a result of chronic puffiness around the eyes, and a crease across the nose from frequently wiping it and pushing it upward.
To identify the specific allergen (allergy-triggering substance) that is triggering your hay fever, your doctor may refer you to an allergist, who can do skin testing. In skin testing, a small amount of a specific allergen is scratched, pricked or injected into the skin. Results are available in 10 to 20 minutes.
Blood tests also can be done to measure eosinophils (a type of white blood cell that increases in number during allergy seasons) or levels of IgE, an allergy-inducing antibody. An elevated eosinophil count or IgE level tells the doctor that there is an allergic response, while skin tests provide more specific information about what the person it allergic to. Blood tests are most helpful when skin testing cannot be done, such as when someone has severe eczema.