Can Hydroxychloroquine Cause Mouth Sores? A Pharmacological Look at Oral Side Effects

October 10, 2025 •

4 min read

Severe skin reactions linked to hydroxychloroquine, though rare, can manifest as blisters and sores in the mouth, eyes, and other areas of the body. This medication is primarily used to treat autoimmune conditions like lupus and rheumatoid arthritis, but patients need to be aware of all potential adverse reactions, especially given the crucial question: Can hydroxychloroquine cause mouth sores?

Quick Summary

Hydroxychloroquine treatment can, in rare cases, lead to oral ulcers and mouth sores, which may be part of a serious mucocutaneous reaction like Stevens-Johnson syndrome. However, the drug is also used to treat certain oral conditions, which can cause confusion. Awareness of the different oral side effects is essential for patient safety.

Key Points

Serious Reactions: Hydroxychloroquine can cause mouth sores as part of rare but severe mucocutaneous reactions, including Stevens-Johnson Syndrome (SJS).
Immediate Attention: If mouth sores appear alongside a fever, widespread rash, or blisters, seek immediate emergency medical care.
Dual Function: Hydroxychloroquine is paradoxically used to treat certain oral conditions, such as Chronic Ulcerative Stomatitis and Oral Lichen Planus.
Oral Hyperpigmentation: Long-term use can cause harmless but noticeable bluish-gray spots on the mouth's mucous membranes.
Manage Mild Symptoms: For less severe oral irritation, maintaining good hygiene and avoiding irritating foods can help, but always consult a doctor first.
Report All Side Effects: Any new or concerning oral symptoms should be reported to your doctor to determine the underlying cause and ensure safety.

Understanding Hydroxychloroquine and Its Uses

Hydroxychloroquine, often known by the brand name Plaquenil, is a medication classified as a disease-modifying anti-rheumatic drug (DMARD) and antimalarial. It is widely prescribed to manage symptoms of autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). While generally considered safe and effective for long-term management of these conditions, like all medications, it carries a risk of side effects. Most side effects are gastrointestinal, such as nausea and diarrhea, but more serious—though infrequent—adverse reactions can also occur, including those affecting the oral cavity.

The Serious Link: Hydroxychloroquine and Mucocutaneous Reactions

While not a common side effect, hydroxychloroquine can trigger severe, potentially life-threatening mucocutaneous reactions that include sores in the mouth. These serious reactions are rare but require immediate medical attention. They include:

Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): These are severe, blistering skin conditions that can also affect the mucous membranes, including the mouth, throat, eyes, and genitals. Blisters, peeling skin, and sores in the mouth are hallmark signs of these conditions. The onset of SJS/TEN can sometimes be preceded by flu-like symptoms, fever, or a rash.
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome: This is another severe drug reaction that can cause a widespread skin rash, fever, and internal organ involvement. Oral manifestations, including sores or ulcers, may also be present.

It is crucial to recognize that the appearance of mouth sores alongside a severe rash or fever while taking hydroxychloroquine is a medical emergency. Patients should seek immediate medical help if they experience such symptoms.

A Complex Picture: HCQ as a Treatment for Oral Lesions

Adding to the complexity, hydroxychloroquine is paradoxically used to treat certain oral conditions that cause ulcers and inflammation. This off-label use highlights the medication's anti-inflammatory and immunomodulatory properties. Conditions that can be treated with HCQ include:

Chronic Ulcerative Stomatitis (CUS): A chronic condition characterized by painful oral ulcerations that often responds to treatment with hydroxychloroquine.
Oral Lichen Planus (OLP): An inflammatory condition affecting the mucous membranes inside the mouth, which can cause painful sores and lesions. HCQ can be an effective treatment in some cases.
Sjögren's Syndrome (pSS): An autoimmune disorder causing dry mouth and eyes. Some studies suggest HCQ can alleviate these symptoms and improve quality of life.

This dual nature—rarely causing mouth sores as a severe side effect while also being a treatment for certain oral conditions—underscores the importance of a proper medical diagnosis. A patient with lupus may develop an oral ulcer for reasons unrelated to the HCQ, while another patient might be prescribed HCQ specifically to heal an oral ulcer caused by CUS.

Other Oral and Dental Side Effects

Beyond the rare but serious reactions, there are other, less severe oral side effects to be aware of when taking hydroxychloroquine.

Oral Hyperpigmentation: Long-term use of hydroxychloroquine, as well as chloroquine, can cause hyperpigmented macules (bluish-gray spots) to appear on the skin and mucous membranes, including the hard palate and tongue. This is not the same as an ulcer but is an oral manifestation of the drug. The risk is dose and duration-dependent.
Dry Mouth (Xerostomia): Although HCQ can treat Sjögren's-related dry mouth, some individuals may experience dryness as a side effect. This can increase the risk of dental problems and mouth irritation.
Increased Risk of Infection: In rare cases, HCQ can cause low blood cell counts, which can lead to an increased risk of infections, including those that manifest as frequent sore throats or mouth ulcers.

Comparison of Hydroxychloroquine Oral Effects


Feature	SJS/TEN-related Mouth Sores	Oral Hyperpigmentation	CUS/OLP-related Ulcers (Treated by HCQ)
Symptom Appearance	Blistering, painful ulcers, often with a severe rash and fever.	Bluish-gray or dark brown macules (spots) on the palate or tongue.	Inflamed, often painful, persistent ulcers.
Severity	Severe, potentially life-threatening medical emergency.	Benign but cosmetically undesirable.	Varies, but HCQ is used to treat and resolve them.
Likelihood	Rare.	Rare, typically associated with long-term use.	Varies by condition; HCQ is the prescribed treatment.
Action Required	Seek emergency medical help immediately.	Discuss with your healthcare provider during a routine visit.	Follow your healthcare provider's instructions for treatment.

What to Do If You Experience Mouth Sores

If you develop mouth sores while taking hydroxychloroquine, it's essential to assess the severity and accompanying symptoms.

Signs of a Serious Reaction

Blisters on the skin, eyes, or inside the mouth
Fever, body aches, or flu-like symptoms
Widespread or worsening rash
Peeling skin
Difficulty swallowing
Swelling of the face, tongue, or throat

If any of these serious signs appear, contact your doctor or seek emergency medical care immediately.

Management of Mild Oral Irritation

If you suspect mild irritation rather than a severe reaction, you can take these steps, but always check with your healthcare provider first:

Maintain excellent oral hygiene.
Rinse your mouth with a saltwater solution.
Use over-the-counter oral pain relief gels or sprays.
Avoid spicy, acidic, or very hot foods.
Stay hydrated by drinking plenty of water.

Conclusion

While the answer to "can hydroxychloroquine cause mouth sores?" is yes, it's important to put this risk in context. The development of mouth sores is rare and most concerning when associated with a severe mucocutaneous reaction like SJS/TEN. However, less severe oral effects, such as hyperpigmentation, are also possible with long-term use. Crucially, in some conditions, hydroxychloroquine is actually prescribed to heal oral ulcers, demonstrating its complex and sometimes paradoxical effects on the oral cavity. For any oral symptoms, especially if accompanied by other serious signs, prompt communication with a healthcare provider is the safest course of action. For more information, refer to a reliable source such as the MedlinePlus drug information page for hydroxychloroquine.

Frequently Asked Questions

No, mouth sores are not a common side effect of hydroxychloroquine. When they do occur, they can sometimes be a sign of a rare but serious mucocutaneous reaction, like Stevens-Johnson Syndrome or Toxic Epidermal Necrolysis.

You should be concerned if mouth sores appear alongside a fever, chills, widespread rash, or blistering and peeling skin. These could be signs of a serious allergic or drug reaction, and you should seek emergency medical help immediately.

Yes, in a medical paradox, hydroxychloroquine is sometimes prescribed to treat inflammatory oral conditions that cause sores and ulcers, such as Chronic Ulcerative Stomatitis (CUS) and Oral Lichen Planus (OLP).

HCQ can cause mouth sores as part of a severe, blistering drug reaction, which is a medical emergency. Other oral effects are different, such as oral hyperpigmentation, which appears as harmless bluish-gray spots from long-term use.

For mild irritation, maintaining good oral hygiene, rinsing with salt water, and avoiding irritating foods can help. However, you should always consult your doctor to ensure the symptoms are not indicative of a more serious issue.

Yes, prolonged use of hydroxychloroquine has been associated with hyperpigmentation, or darkening, of the oral mucosa, particularly on the palate.

In patients with Sjögren's Syndrome, studies have shown that hydroxychloroquine can help to alleviate symptoms like dry mouth and dry eyes. However, some individuals may experience dry mouth as a general side effect.