Allergic rhinitis, the fifth most common chronic disease in the United States, is an immunoglobulin E–mediated process. A family history of allergic rhinitis, asthma, or atopic dermatitis increases a patient's risk of being diagnosed with allergic rhinitis. People in the United States are commonly sensitized to grass, dust mites, and ragweed allergens. Dust mite–proof mattress covers do not prevent allergic rhinitis in children two years and younger. Diagnosis is clinical and based on history, physical examination, and at least one symptom of nasal congestion, runny or itchy nose, or sneezing. History should include whether the symptoms are seasonal or perennial, symptom triggers, and severity. Common examination findings are clear rhinorrhea, pale nasal mucosa, swollen nasal turbinates, watery eye discharge, conjunctival swelling, and allergic shiners (i.e., dark circles under the eyes). Serum or skin testing for specific allergens should be performed when there is inadequate response to empiric treatment, if diagnosis is uncertain, or to guide initiation or titration of therapy. Intranasal corticosteroids are first-line treatment for allergic rhinitis. Second-line therapies include antihistamines and leukotriene receptor antagonists and neither shows superiority. If allergy testing is performed, trigger-directed immunotherapy can be effectively delivered subcutaneously or sublingually. High-efficiency particulate air (HEPA) filters are not effective at decreasing allergy symptoms. Approximately 1 in 10 patients with allergic rhinitis will develop asthma.