Itching of the roof of the mouth is a common symptom of allergic rhinitis, a condition in which the immune system reacts to external or internal allergens, such as pollens, mold and dust mites, according to Avera Health. Additional symptoms include nasal congestion, watering eyes and sneezing.
Individuals who suffer from seasonal allergies may also experience itching on the roofs of their mouths if they ingest fruits like apples and melons, according to WebMD. The condition is referred to as oral allergy syndrome and occurs when sensitive individuals eat fruits, vegetables or plants that contain proteins that are similar to outdoor pollens, such as ragweed and grass. Additional fruits and vegetables that can cause oral allergy symptoms include celery, tomatoes, kiwi fruit and carrots.
Additional oral allergy symptoms include scratchy throat, swollen lips, tongue swelling and itching ears, according to the American College of Allergy, Asthma and Immunology. The condition is common in older children, teenagers and young adults. Individuals with oral allergy syndrome can often ingest cooked vegetables and fruits that contain the allergen proteins and not experience allergic reactions, as the cooking process alters the substances. In most cases, oral allergy symptoms dissipate as soon as the food is swallowed and no longer in contact with the oral tissues.