Trees: Pollinate April and May. Common allergy causing trees include oaks, elms, birches and maples.
Grasses: The last week of May thru July is typically a time when people allergic to grasses experience the most severe allergy symptoms. More people are allergic to grass than anything other allergen. Highly allergenic grasses include Bluegrass, Timothy, Meadow Fescue, Johnson, Rye, Redtop, Orchard, and Bermuda. When the season finally ends with a hard freeze, these allergy symptoms generally go away.
Weeds: The season starts in late July and goes until the hard freeze. In our region, ragweed allergies hit hard around August 15 each year. Other common allergy-causing weeds include kochia, Lamb’s quarters, Russian thistle, pigweed, dock, marsh elder and nettle.
Molds: There are thousands of types of molds. The majority of them are outdoor allergens that cause the greatest allergy symptoms in the summer and fall. Examples are the molds Alternaria, Hormodendrum, and Helminthosporium. Unlike weeds, the mold season will continue after the freeze until after Halloween. Other molds grow and release their spores into the indoor air to give year-round symptoms.
Pets: Pets are a common cause of year-round allergy and asthma symptoms. Cats, dogs, hamsters, guinea pigs, rats, and most furry pets can cause allergies. It generally takes special cleaning and months to decrease the allergy level once the pet is out of the house to see an improvement.
Dust Mites: Dust mites live in pillows, mattresses, carpets and furniture. Special encasements and frequent washing of bedding can help.