by MARBLE
By Marble
Hi,
I have taken metformin for perhaps nine years. In 2007, I was diagnosed with oral lichen planus. It was controlled for a while, but I lost my job and insurance and could no longer visit the dentist or obtain medicine.
I thought I was fine and did not understand how it could appear. My hair became brittle and fell out. Thyroid and other tests found no cause.
Suddenly, my mouth became raw, red and sensitive to salt, vinegar and other foods. A bad taste changed the flavor of everything I ate. Even cigarettes became unbearable.
I receive Veterans Hospital care but lack dental privileges. My primary-care clinician knew little about this condition. I requested my former prescriptions and am coordinating with my previous dentist.
Along with the tongue and cheek problems, I have had a sore throat for months. I believe these problems may be related. Thank you for this site; without it, I would not have understood the possible causes.
Quick answer: Oral lichen planus can flare and persist for years. A raw red mouth can fit erosive disease, but infection, a medicine-related reaction and precancerous or cancerous changes may look similar. Months of sore throat—especially with smoking—requires prompt oral medicine or ENT assessment. Scalp lichen planus can cause permanent scarring hair loss and needs early dermatology review.
Hi Marble,
Your symptoms need coordinated specialist care. Contrary to the earlier answer, oral lichen planus is often chronic, with improvement and flare-ups. Stress may aggravate it but should not explain away persistent red or painful lesions.
Oral lichen planus may cause lacy white lines, red areas, erosions or ulcers on the cheeks, tongue and gums. Erosive disease often burns with acidic, spicy, salty, coarse or hot foods. Taste may change with inflammation, dry mouth, infection, smoking or medicines.
Oral candidiasis, nutritional deficiency, contact allergy, lupus and lichenoid drug reactions can resemble it. Persistent lesions also need examination for dysplasia or cancer. Do not restart an old prescription without a current examination.
Biopsy is useful when diagnosis was never confirmed microscopically, the appearance is atypical, treatment fails or a lesion changes. It can distinguish lichen planus from dysplasia, cancer and other disorders. Swabs may check suspected infection.
Routine biopsy every six or twelve months is not required for unchanged lesions. Regular follow-up and prompt biopsy matter for a persistent ulcer, lump, hardened area, bleeding, or changing red, white or mixed patch.
The cancer risk is low but real. A 2024 review estimated malignant transformation at about 1.4%. Risk is higher with red or erosive disease, tongue involvement, smoking and alcohol. This does not mean you have cancer, but long-term monitoring matters.
A months-long sore throat should not be assumed to be lichen planus. Ask promptly for ENT or oral medicine referral, particularly because you smoke. The mouth, tongue base, tonsils, throat and neck need examination.
Seek urgent assessment for pain or difficulty swallowing, persistent hoarseness, one-sided throat or ear pain, a neck lump, unexplained weight loss, bleeding, or an ulcer lasting more than three weeks. Seek emergency help if you cannot swallow saliva, have trouble breathing or develop rapidly increasing tongue or neck swelling.
Some medicines trigger lichenoid reactions resembling lichen planus. A timeline of prescriptions, nonprescription medicines and supplements is important. Metformin is not a common established cause, and years of use before symptoms makes a direct link less obvious.
Do not stop metformin yourself. Your prescriber can review the timing, examine the lesions and decide whether a supervised medication change is justified. Other medicines—especially blood-pressure drugs, anti-inflammatory medicines and recently started treatments—must also be reviewed. See the guide to metformin side effects.
Oral lichen planus is not considered a routine complication caused directly by diabetes. Research has reported associations, but it does not prove that diabetes caused your condition. High glucose can worsen dry mouth, oral infection and healing, so good diabetes management remains helpful.
Topical corticosteroids are commonly used for painful erosive disease. They may encourage oral thrush, and stronger or systemic steroids may raise blood glucose. Tell the treating clinician that you have diabetes and ask how often to monitor glucose during treatment.
Hair loss is not explained by oral lichen planus alone. Lichen planus affecting the scalp is called lichen planopilaris. It may cause scalp redness, scaling, itching, burning, tenderness and patchy hair loss. Because it can scar follicles and make hair loss permanent, early dermatology treatment is important.
Other causes—including iron or vitamin deficiency, medication effects, illness, hormonal changes and common non-scarring hair loss—should also be considered. A dermatologist can examine the scalp and decide whether a scalp biopsy or further blood tests are appropriate.
Written by Dr. Albana Greca Sejdini, MD, MMedSc
Medically reviewed by Dr. Ruden Cakoni, MD, Endocrinologist
Last reviewed: July 2026
Educational only—not personal medical advice. Persistent mouth, throat or scalp symptoms require examination by qualified healthcare professionals.
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