Seasonal Allergies

Allergic rhinitis is an allergic response to outdoor allergens. Seasonal allergic rhinitis occurs only during periods of intense airborne pollen or spores. It is commonly, although inaccurately, called hay fever, triggers of seasonal allergy in the U.S. include:

  • Ragweed is the most dominant cause of allergic rhinitis in the U.S., affecting about 75% of allergy sufferers. One plant can release 1 million pollen grains a day. Ragweed occurs everywhere in the U.S., although it is less common in western coastal states, southern Florida, northern Maine, Alaska, and Hawaii. The effects of ragweed in the northern states are first felt in middle to late August and last until the first frost. Ragweed allergies tend to be most severe before midday.
  • Grasses affect people in mid-May to late June. Grass allergies are experienced more in the late afternoon.
  • Tree pollen grains from certain trees usually produce symptoms in late March and early April.
  • Mold spores that grow on dead leaves and release spores into the air are common allergens throughout the spring, summer and fall. Mold spores may peak on dry windy afternoons or on damp or rainy days in the early morning.

Risk Factors

Allergic rhinitis affects about 50 million Americans of all ages. As with asthma and many upper respiratory infections, the incidence in allergic rhinitis is increasing. Allergies most often appear first in childhood, and allergic rhinitis is the most common chronic condition in childhood, although it can develop at any age. About 20% of allergic rhinitis cases are due to seasonal allergies, 40% to perennial (chronic) rhinitis, and the rest are mixed. Allergic rhinitis appears to have a genetic component. People with a parent who has allergic rhinitis have an increased risk of developing allergic rhinitis themselves. The risk increases significantly if both parents have allergic rhinitis.


Treatment options include, environmental control measures, nasal washes, drugs that reduce the inflammatory response are important for preventing moderate or severe allergic rhinitis Nasal corticosteroids (commonly called steroids) are now considered to be the most effective measure for preventing allergy attacks. Antihistamines relieve sneezing and itching and can prevent nasal congestion before an allergy attack, or may be used to treat symptoms. Immunotherapy (“allergy shots”) may be considered as well. They may also prevent or help manage asthma and the development of new allergies in children.