Yes, allergies can cause pain and discomfort in the mouth and throat. An allergy is an immune system overreaction where a harmless substance, such as pollen or dust, is mistakenly identified as a threat. The body launches a defensive response that frequently impacts the respiratory tract and adjacent structures, including the oral cavity and pharynx. This reaction can lead to acute symptoms or trigger events that result in referred pain and chronic soreness.
How General Allergic Inflammation Causes Oral Discomfort
The most common way generalized allergies, like hay fever, lead to discomfort is through the body’s inflammatory response. Upon exposure to an allergen, immune cells release chemicals, including histamine, which are responsible for the familiar allergy symptoms. Histamine increases blood flow to the affected tissues, causing localized swelling and a sensation of itching or irritation in the nose, throat, and sometimes the soft palate.
This inflammatory process increases mucus production in the nasal passages and sinuses. When this excess mucus cannot drain forward, it flows down the back of the throat, a phenomenon known as post-nasal drip (PND). The mucus irritates the delicate mucous membranes of the pharynx and soft palate. This persistent irritation can lead to a chronically sore, scratchy, or raw sensation that is often worse upon waking.
The inflammation caused by PND can also affect the tonsils and throat tissues, leading to swelling and a feeling of a lump or tightness in the back of the mouth. This physical irritation prompts frequent swallowing or throat clearing, which further exacerbates the soreness.
Oral Allergy Syndrome and Cross-Reactivity
A more direct and acute form of allergy-related mouth pain is known as Oral Allergy Syndrome (OAS), also called Pollen-Food Syndrome. This condition occurs in individuals sensitive to airborne pollens, particularly those with allergies to birch, grass, or ragweed pollen. The symptoms are triggered by eating certain raw fruits, vegetables, or nuts that contain proteins similar to the patient’s primary pollen allergen.
This mechanism is called cross-reactivity. The immune system’s antibodies mistakenly recognize similar proteins in raw foods like an apple or carrot. Because the food proteins are easily broken down by heat, OAS symptoms typically only occur when the food is eaten raw, as cooking denatures the offending protein structure. The reaction is generally localized and mild, occurring immediately upon contact with the mouth tissues.
OAS manifests as immediate itching, tingling, or a burning sensation on the lips, tongue, or the roof of the mouth. Some people may also experience mild swelling of the lips or throat, which can feel like acute discomfort or pain. For individuals allergic to birch pollen, common cross-reacting foods include:
- Almonds
- Apples
- Cherries
- Carrots
The symptoms usually subside quickly once the food is swallowed or removed, making it a contact allergy confined to the oral cavity.
Secondary Effects That Lead to Mouth Pain
Several secondary effects of allergies and their treatments can cause pain in the mouth area. One common issue is referred pain originating from sinus congestion. The maxillary sinuses are positioned directly above the upper back teeth, separated only by a thin layer of bone. When allergies cause inflammation and fluid buildup in these sinuses, the resulting pressure can press down on the roots of the upper teeth.
This pressure is often mistaken for a dental problem, presenting as a dull ache or throbbing pain that affects several upper teeth simultaneously. The pain is not caused by tooth decay but by the proximity of the sinus cavity to the dental nerves. Treating the underlying sinus inflammation is the most effective way to relieve this referred dental pain.
Another cause of oral discomfort is mouth breathing, which occurs when nasal passages are blocked by allergy-induced congestion. Breathing through the mouth for extended periods, especially overnight, causes the mouth to dry out. Saliva is a natural protector, and its reduction leads to a dry mouth condition known as xerostomia.
This lack of moisture causes the sensitive tissues of the mouth, including the gums, tongue, and throat, to become dry, irritated, and sore. Many common allergy medications, particularly certain antihistamines, can exacerbate this problem by inhibiting saliva production as a side effect. This medication-induced dry mouth can increase the risk of gum inflammation and overall oral soreness.