Hydroxychloroquine and oral lichen planus reactions
Why hydroxychloroquine can cause white lacy patches and lichenoid lesions in the mouth, how they look, and what to do about them.
Never start, stop, or change a medication based on what you read here. Bring questions to your dentist, physician, pharmacist, or prescribing clinician.
Quick answer
Hydroxychloroquine (Plaquenil) is a recognized cause of oral lichenoid reactions, which look like and behave like oral lichen planus: white lacy patches, redness, or shallow ulcers, usually on the inner cheeks or tongue. The reactions can be painful or asymptomatic. They are not contagious and not cancer, but they can mimic other serious conditions and should be evaluated. Most cases improve when the medication is stopped or substituted, but stopping is not always an option for the underlying autoimmune disease.
The mechanism
Why hydroxychloroquine causes lichenoid reactions
Hydroxychloroquine modulates the immune system, which is why it is used for lupus, rheumatoid arthritis, and other autoimmune conditions. In a small subset of patients, the medication appears to trigger an inflammatory reaction in the oral lining that closely resembles spontaneous oral lichen planus. The cells of the immune system (particularly T-cells) attack the basal layer of the mouth lining, producing the characteristic white lacy striations and sometimes red or ulcerated areas.
The lesions tend to appear on the inner cheeks, the sides of the tongue, the gums, or the palate. They can range from asymptomatic white patches that a dentist notices during a routine exam to painful ulcerative areas that interfere with eating. The pattern often suggests medication-related rather than spontaneous lichen planus, particularly when it appears within months of starting hydroxychloroquine and resolves on stopping.
Hydroxychloroquine can also rarely cause blue-gray pigmentation of the palate and gums with long-term use, a separate but related effect. This pigmentation is largely cosmetic and is not a sign of disease, but it should be documented so it is not mistaken for melanoma or other concerning pigmented lesions.
Practical steps
What to do about lichenoid reactions on Plaquenil
Signs to watch for
When to call your dentist
- White lacy patches in the mouth that have been present more than two weeks.
- Painful red areas or shallow ulcers that recur or do not heal.
- New blue-gray pigmentation on the palate or gums.
- Lesions that change in appearance over time, especially becoming firmer or more raised.
- Difficulty eating or speaking because of mouth discomfort.
Common questions
What patients ask about Hydroxychloroquine (Plaquenil) and oral lichen planus reactions
KYT Framework
KYT Framework connection
Four questions that shape how Hydroxychloroquine (Plaquenil) and oral lichen planus reactions factor into dental planning.
Structure
Does oral lichen planus reactions change bone, gum tissue, saliva, enamel, or healing support?
Force
Will chewing, grinding, or bite pressure create added risk for vulnerable teeth or healing tissue?
Timing
Is oral lichen planus reactions something to prevent now, monitor, or evaluate soon?
Stability
What plan gives the mouth the best chance to stay stable?
Next steps
What to do about oral lichen planus reactions
The medication side is usually not the right thing to change. The dental side is. Here is where to go next.
Condition
Oral lichen planus
What it looks like, lichenoid drug reactions, and monitoring cadence.
Open →Monitoring
Periodic monitoring exams
Why patients with lichen planus need exams more often than the general population.
Open →Next step
Initial evaluation
First visit confirms the pattern and rules out other lookalikes.
Open →More about Hydroxychloroquine (Plaquenil)
Other medications and oral lichen planus reactions
Taking Hydroxychloroquine (Plaquenil) and noticing oral lichen planus reactions changes?
Bring your medication list. KYT can evaluate cavity risk, gum health, and treatment timing in person.
Reviewed by Dr. Isaac Sun, DDS · KYT Dental Services · Fountain Valley, CA · Last reviewed: June 2026
This page is general patient education. It does not replace advice from your prescribing clinician, physician, pharmacist, or dentist. Medication information may change; verify with your clinical team.