Why Do I Have a Rash in My Mouth?

You notice an irritated patch inside your cheek while brushing your teeth. Is it serious? Should you be worried? Understanding what causes mouth rashes can help you determine your next steps.

Rashes are skin conditions that everyone must deal with at one time or another in their lifetime, and the causes range from mosquito bites and poison ivy to chronic skin ailments such as eczema or psoriasis.

These patches of irritated, inflamed, or itchy skin can appear anywhere from our toes to our scalps, including inside our mouths. They may present as red or bumpy areas, blistering, scaling, or painful spots.

But what exactly constitutes a "rash" inside the mouth?

“The term “rash” in the mouth may cover many things: red or white patches, ulcerations, mucosal inflammation, irritation, blistering, etc. Broadly speaking, mucosal lesions of the oral cavity are common,” explained Dr. Stephen C. Dwyer of Northwest Oral and Maxillofacial Surgery.

Most rashes in the mouth are caused by irritants such as poorly fitting dentures, dental devices such as braces and retainers, sharp or broken teeth, tobacco products, or even damage from hot food or beverages.

“Most rashes in your mouth have benign causes, but if you get frequent mouth rashes, or have a mouth rash that is getting worse or causing you concern, then reach out to a healthcare professional today,” said Dr. Dwyer.

Non-Disease Causes of a Rash in the Mouth

There are many non-disease causes of a rash in the mouth that come from external or irritation factors, such as:

• Highly acidic or irritating foods and beverages: Foods that are high in acid (such as citrus fruits, tomatoes, vinegar, soda, etc.) can irritate the mucous membranes of the mouth, leading to redness, soreness, and small superficial erosions.
• Trauma, friction, or thermal injuries: Hot food and drink, overly vigorous tooth brushing, cheek or tongue biting, and sharp edges from a tooth or dental appliances such as braces can all lead to rashes.
• Allergies and contact irritation: Some mouth rashes result from allergic or irritant reactions to toothpaste ingredients, mouth wash, flavorings, chewing gum additives, food additives, or dental materials.
• Certain medications and dry mouth effects: Many medications reduce the salivary flow which lessens the protective buffer in the mouth, making mucosa more vulnerable to irritation.
• Nutritional deficiencies and lifestyle triggers: Deficiencies of folate, B12, iron, and zinc are associated with more frequent mucosal lesions. Rashes have also been attributed to hormonal fluctuations, stress, fatigue, poor sleep, and poor oral hygiene.

Good oral hygiene, stress reduction, and a balanced diet are effective starting points for preventing mouth rashes.

Medical Conditions That Can Cause a Rash in Your Mouth

If your mouth rash is persistent and the cause remains unclear, you may need a dental or medical professional to examine you. There are many disease-related causes of mouth rashes:

• Oral candidiasis (thrush): White, creamy patches (sometimes red underneath) may bleed when scraped. This is caused by the overgrowth of yeast in the oral cavity.
  Treatment: Topical antifungals and addressing the underlying cause such as controlling diabetes, rinsing your inhaler if on steroids, and improving denture hygiene.
• Recurrent canker sores: Minor trauma, acidic foods, stress, nutritional deficiency, hormonal changes, and toothpaste additives are just some of the causes of canker sores, which present as small oval ulcers with gray or yellow centers and a red halo. The good news is that these are non-infectious, but they can be painful. 
  Treatment: Topical protective gels and antiseptic mouth rinses while avoiding triggers.
• Oral lichen and other immune-mediated mucosal diseases: Oral lichen planus (OLP) is an immune-mediated chronic condition that can cause reticular white lace-like patterns in mucosa. Other mucosal immune diseases that can cause rashes include mucous membrane pemphigoid and pemphigus vulgaris.
  Treatment: Depends on the extent or severity. A specialist will determine a course of action such as topical steroids and systemic therapy.
• Infections and systemic disease: Viral infections (Herpes simplex for example) or bacterial infections can cause a rash in your mouth. Many autoimmune or gastrointestinal diseases may first present in the mouth such as Behçet's disease, Celiac disease, and inflammatory bowel disease. Precancerous legions (oral leukoplakia) can also form in the mouth.
  Treatment: Referral to an oral surgeon or other medical professional is necessary whenever persistent, unexplained mucosal changes appear.

How to Treat Your Mouth Rash at Home

For many mouth rashes, at-home treatment can address the problem. Some steps you can take before seeking professional care include:

• Avoid known irritants such as acidic foods, mouthwashes with alcohol, very spicy food, crunchy or hard foods, and very hot food and beverages.
• Improve your oral hygiene by brushing gently, avoiding abrasive toothpaste, flossing daily, and keeping dental appliances clean.
• Rinse or gargle with warm salt water once or twice daily to soothe irritation.
• Use over-the-counter soothing agents such as topical analgesic rinses or protective pastes designed for oral use.
• Stay hydrated and maintain saliva flow by drinking water throughout the day.
• Review your medications and hygiene products for potential irritants that may be contributing to the rash.
• Ensure adequate intake of key nutrients including B12, folate, iron, and zinc, which support healthy oral tissue.
• Manage stress levels through relaxation techniques, adequate sleep, and healthy lifestyle habits.

If your mouth rash does not clear up within a week or two, worsens despite home care, or causes significant pain, schedule a visit with your dentist or doctor. They can help identify the underlying cause of your mouth rash and prescribe an appropriate treatment plan, which may include anti-inflammatory or pain-relieving medications.

When to Seek Professional Advice

Home care alone may not be sufficient to resolve your mouth rash. Schedule a healthcare appointment if you have a rash accompanied by any of the following signs:

• A rash or single lesion that persists for more than two to three weeks without improvement, or if you have lesions that are multiplying.
• Significant pain, bleeding, or difficulty eating or drinkingthat interferes with your daily activities.
• White or red patches that persist, especially if they are unilateral or asymmetrical.
• New lumps, nodules, or ulcerations in the mouth that don't relate to a minor irritant cause.
• Systemic symptoms such as fever, weight loss, night sweats, or lymph node swelling.
• You are immunocompromised (due to HIV, organ transplant, or chemotherapy) or are taking immunosuppressive medications.
• The rash recurs frequently, and you cannot identify a clear trigger.
• You have risk factors for oral cancer (tobacco use, heavy alcohol use, or betel nut chewing) and lesions persist.
• You suspect medication or allergic cause, and the lesions are spreading or worsening.

In many of these cases, your oral surgeon will want to perform an evaluation and possibly a biopsy to diagnose the underlying cause and formulate an appropriate treatment plan.

Northwest Oral Surgery Can Help

Most mouth rashes resolve with simple home care and lifestyle adjustments. However, persistent or concerning symptoms warrant professional evaluation.

If you're experiencing a mouth rash that won't heal or causes you concern, contact Northwest Oral and Maxillofacial Surgery today. Our board-certified surgeons at six convenient locations can provide expert diagnosis and treatment to restore your oral health and peace of mind.