ConditionSkin, hair & nails
Lichenoid Drug Eruption
A lichenoid drug eruption is a skin reaction to a medicine that looks like lichen planus: itchy, flat-topped, purple, red or brown bumps and scaly patches. It often appears months after starting the drug, which makes the link easy to miss. Common culprits include some blood pressure medicines, antimalarials, cancer immunotherapy and certain diabetes and arthritis drugs. The rash usually clears after the medicine is stopped or switched, though this can take weeks to many months and often leaves dark marks.
Also called: Drug-induced lichen planus, lichenoid drug reaction, lichenoid dermatitis from medication
At a glance
- What it is
- A lichen planus-like rash triggered by a medicine.
- Onset
- Usually months (sometimes over a year) after starting the drug.
- Common culprits
- Beta-blockers, ACE inhibitors, thiazides, antimalarials, NSAIDs, TNF inhibitors, checkpoint inhibitor immunotherapy, gold, some diabetes drugs.
- Appearance
- Itchy, flat, violet, red-brown or scaly bumps and plaques, often widespread and in sun-exposed areas.
- Diagnosis
- Skin biopsy plus careful medication history.
- Treatment
- Stop or replace the drug when possible; steroid creams and antihistamines for symptoms.
When to get help
Call 911 or go to the ER
- A rash with blistering, peeling skin, sores in the mouth, eyes or genitals and fever (possible Stevens-Johnson syndrome)
- Facial swelling, difficulty breathing or widespread hives after a medicine
See a doctor within a day or two
- A widespread rash with fever, swollen glands or feeling unwell after starting a medicine (possible DRESS)
- A rash on immunotherapy for cancer: tell your oncology team promptly
Book a routine appointment
- A new itchy, purplish or scaly rash months after starting a regular medicine
- Painful white lacy patches or sores in the mouth while on a new medicine
- A rash that has not improved after weeks of treatment
What a lichenoid drug eruption is
"Lichenoid" means resembling lichen planus. In both, immune T cells attack the base of the outer skin layer, producing a characteristic pattern under the microscope. In a lichenoid drug eruption, a medicine triggers this reaction. Unlike an allergic hive reaction, it develops slowly, often months after the drug was started, and also clears slowly after stopping.
Medicines that can cause it
| Drug group | Examples |
|---|---|
| Blood pressure and heart medicines | Beta-blockers, ACE inhibitors (especially captopril), thiazide diuretics, calcium channel blockers |
| Antimalarials | Hydroxychloroquine, chloroquine, quinine |
| Cancer treatments | Checkpoint inhibitors (pembrolizumab, nivolumab), imatinib and other targeted drugs |
| Anti-inflammatory and arthritis drugs | NSAIDs, gold salts, TNF inhibitors, penicillamine, sulfasalazine |
| Diabetes medicines | Sulfonylureas, some DPP-4 inhibitors |
| Others | Lithium, some anti-tuberculosis drugs, some statins, proton pump inhibitors, and some antiretrovirals |
Many other drugs have been reported. Any medicine started in the past year or two should be considered.
Symptoms
- itchy, flat-topped bumps that may merge into scaly patches
- violet, red-brown or grayish color; on darker skin, often dark brown or gray
- often widespread and symmetrical on the trunk and limbs
- sometimes worse on sun-exposed skin (photo-lichenoid eruption, for example with thiazides or quinine)
- less commonly, mouth involvement: white lacy streaks or sores, especially with metal dental fillings or certain drugs
- nail changes or hair loss occasionally
Lichenoid drug eruption vs lichen planus
| Lichenoid drug eruption | Lichen planus | |
|---|---|---|
| Trigger | A medicine | Usually unknown |
| Distribution | Widespread, may favor sun-exposed areas | Wrists, ankles, lower back, mouth, genitals |
| Appearance | More scaly, eczema-like; fewer white Wickham striae | Shiny, flat, violet bumps with white streaks |
| Mouth involvement | Less common | Common |
| Course | Clears after stopping the drug | May last 1 to 2 years or longer |
| Biopsy | Often shows eosinophils and other drug features | Classic lichen planus pattern |
Diagnosis
- Medication history: every prescription, over-the-counter medicine and supplement taken in the past 1 to 2 years, with start dates.
- Skin examination.
- Skin biopsy: confirms a lichenoid pattern; certain features favor a drug cause.
- Blood tests may check for hepatitis C, which is linked to lichen planus.
- Response to stopping the suspected drug is the most convincing confirmation. Re-challenge is generally not recommended.
Treatment
Stop or switch the medicine
With your prescribing doctor's advice, the suspected drug is stopped or replaced with an alternative from a different class. Never stop a medicine such as a heart drug or cancer treatment without medical guidance. In cancer immunotherapy, mild reactions are often treated without stopping treatment, because the cancer benefit is important.
Relieve symptoms
- potent topical corticosteroids on itchy patches
- oral antihistamines for itch
- gentle skin care and moisturizers
- sun protection, especially for photo-lichenoid eruptions
- steroid mouthwashes or gels for mouth involvement
Widespread or severe eruptions
- a short course of oral corticosteroids
- phototherapy
- other systemic treatments such as acitretin in persistent cases
Outlook
Most lichenoid drug eruptions clear within weeks to a few months after stopping the drug, though some take a year or more. Dark marks (post-inflammatory hyperpigmentation) often remain for months, especially on darker skin, and fade slowly with sun protection. The reaction may return if the same or a similar drug is taken again, so record it in your medical notes, as you would any drug allergy or reaction.
Frequently asked questions
What is a lichenoid drug eruption?
It is a skin rash caused by a medicine that looks like lichen planus, with itchy, flat, purple or reddish-brown bumps and scaly patches. It usually appears months after starting the drug and clears slowly after stopping it.
Which drugs cause lichenoid drug eruptions?
Common causes include beta-blockers, ACE inhibitors, thiazide diuretics, antimalarials such as hydroxychloroquine, NSAIDs, TNF inhibitors, cancer immunotherapy drugs, gold salts and some diabetes medicines. Many other drugs have been reported.
How long does a lichenoid drug eruption last?
After the medicine is stopped, the rash usually improves over weeks to a few months, though some cases take a year or more. Dark marks can remain for months afterward and fade gradually.
How is it different from lichen planus?
A lichenoid drug eruption is caused by a medicine, tends to be more widespread and scaly, often affects sun-exposed skin and rarely involves the mouth. Lichen planus has no clear trigger, favors the wrists, ankles and mouth, and has a classic appearance.
Should I stop my medicine if I get a lichenoid rash?
Talk to your doctor first. Some medicines, such as heart drugs or cancer treatments, should not be stopped suddenly. Your doctor can confirm the diagnosis and switch you to a safe alternative or manage the rash while you continue treatment.
Sources
This guide was written from current patient and clinical guidance, including:
- DermNet: Lichenoid drug eruption
- American Academy of Dermatology: Lichen planus, causes
- American Osteopathic College of Dermatology: Lichenoid drug eruption
- MedlinePlus: Lichen planus
- British Association of Dermatologists: Lichen planus patient information