Grass Allergy

Grass pollen is known to cause a variety of different allergic reactions. Grass pollen is present in the air in the late spring and early summer months, which can cause allergic rhinitis, allergic conjunctivitis and asthma. Direct skin contact with grass, from sitting in the grass or mowing the lawn, can cause itching of the skin -- urticaria and atopic dermatitis. Grass allergy can also be associated with the fruit pollen syndrome resulting in food allergies to tomatoes, potatoes and peaches. Grass pollen is usually the predominant pollen in the air during the summer. Allergy to this pollen can cause sneezing, runny nose and itchy eyes, as well as asthma attacks in some people.

Grasses can be divided into two major classes: northern and southern grasses. Northern grasses are common in colder climates, and include timothy, rye, orchard, sweet vernal, red top and blue grasses. Southern grasses are present in warmer climates, with Bermuda grass being the major grass in this category. Most people with significant grass allergy are allergic to most, if not all grasses, on allergy testing, because grass pollens have very similar proteins that cause allergies.

Learn more about pollen allergy.

Grass is unique in that it is one of the only plants that we frequently have direct skin contact with. Blades of grass have microscopic barbs that, when in direct contact with the skin, can result in allergic reactions in the skin, such as itching, urticaria and atopic dermatitis. Oral antihistamines are helpful for the treatment of itching and urticaria with direct grass exposure, and are especially effective when combined with quick bathing and/or changing clothes after significant grass exposure, such as after a soccer game.

Learn more about allergic skin rashes.

Allergies to grass can predispose a person to the oral allergy syndrome (OAS) caused by cross-reactivity between proteins in fresh fruits and vegetables and grass pollen. Grass pollen allergy is associated with OAS to tomatoes, potatoes and peaches. The proteins in the fruits and vegetables that cause OAS are easily broken down with cooking or processing; therefore symptoms don’t usually occur with cooked or processed foods like tomato sauce.

When a fresh tomato is eaten however, a person may experience itching, burning, or stinging sensations of the mouth, throat and tongue. The symptoms generally last only a few seconds or minutes, as the proteins that cause the symptoms are broken down quickly by saliva. Anaphylaxis from OAS is rare, but can occur.

Learn more about the oral allergy syndrome.

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