An itchy mouth is a common symptom of viral or fungal infections. It also frequently occurs during allergic reactions.

Itchiness within the mouth can range from mild to severe, depending on the underlying issue.

In this article, we explore the causes of an itchy mouth. We also describe treatment options, strategies for prevention, and when to see a doctor.

Several conditions can cause itchiness within the mouth, including the following:

Oral allergy syndrome

a man with an itchy mouth seeing a dentist.
A person with an itchy mouth may have a viral or fungal infection or an allergy.

Oral allergy syndrome (OAS) is a type of food allergy that affects the mouth, lips, tongue, and throat. It occurs in people with pollen allergies.

OAS can, for example, cause a person with hay fever — or allergic rhinitis — to experience an allergic reaction to apples or celery.

Proteins in specific foods can be very similar to proteins in certain pollens. In a person with OAS, the body reacts to proteins in these foods as though they were proteins in pollen allergens. This misidentification could result in a new allergic reaction or cause existing allergy symptoms to intensify.

According to the , OAS affects 50–75% of adults who are allergic to birch tree pollen.

Tingling and itching in the mouth are among the most common symptoms of food allergies, according to a .

Other symptoms of OAS can include:

  • a scratchy throat
  • red, itchy bumps called hives that develop in the mouth or throat
  • swelling of the lips, tongue, or throat

that can cause OAS reactions include:

  • nuts
  • apples
  • celery
  • legumes
  • fish and shellfish
  • eggs
  • cow's milk
  • soy
  • wheat

Learn more about the causes and symptoms of OAS here.

Anaphylaxis

woman holding her head and wondering why am i dizzy
A person with anaphylaxis may experience dizziness, a rapid heartbeat, and nausea.

Anaphylaxis is another allergic reaction, but it is far more serious than OAS and requires immediate medical attention. People are at risk of anaphylaxis when their immune system becomes hypersensitive to acute allergens, such as bee stings, pollen, and certain foods.

Anaphylaxis affects the entire body and can cause low blood pressure and severe swelling. The dramatic drop in blood pressure can starve the organs and tissues of oxygen.

The swelling can affect the mouth and throat, making it difficult or even impossible to breathe.

Symptoms of anaphylaxis include:

  • itching or tingling of the mouth and throat
  • hives
  • dizziness
  • rapid heartbeat
  • nausea or vomiting
  • difficulty breathing
  • loss of consciousness

Viral infection

Viruses that attack the upper respiratory tract, such as those responsible for the common cold or flu, can cause an itchy mouth.

When a person gets a viral infection, the immune system sends specialized cells to capture and destroy the invading pathogens.

The buildup of immune cells can lead to inflammation and congestion, which can cause the roof of the mouth and the throat to feel itchy.

Viral infections can cause the following symptoms:

Oral thrush

Oral thrush is a fungal infection that occurs due to an overgrowth of Candida yeasts in the mucous membranes that line the mouth and throat.

Oral thrush causes thick, cream-colored patches on the tongue, inner cheeks, roof of the mouth, and throat. People may experience itching, burning, or general discomfort in the affected areas.

Other symptoms of oral thrush include:

  • dry mouth
  • soreness in the affected areas
  • loss of taste
  • pain while eating or swallowing

The state that the following factors can increase a person's risk of developing oral thrush:

  • wearing dentures
  • smoking
  • taking antibiotics
  • taking corticosteroids, including those in asthma inhalers
  • having diabetes
  • having a weakened immune system

Here, find out more about oral thrush, including home remedies that can help.

Allergy tests help identify specific allergens to avoid. A doctor can use the results to make a diagnosis and, possibly, prescribe epinephrine.

Learn more about epinephrine here.

A physical examination and a culture test help a doctor diagnose oral thrush. During a culture test, a doctor often uses a cotton swab to collect a small sample from the patches in the mouth, which goes to a laboratory for analysis.

The doctor may also request a blood test to rule out any underlying conditions.