What Drugs Cause Lichen Planopilaris? Identifying the Culprits

While cutaneous lichen planus affects less than 1% of the population, a drug-induced form known as a lichenoid drug eruption can lead to permanent hair loss [1.6.5]. Understanding what drugs cause lichen planopilaris is key to diagnosis and management.

Quick Summary

A detailed look at the medications and drug classes associated with triggering lichen planopilaris (LPP), a form of scarring alopecia. The article outlines common culprits, diagnosis, and management strategies for drug-induced LPP.

Key Points

• Primary Cause: Lichen planopilaris (LPP) can be a drug-induced condition known as a lichenoid drug eruption, caused by an immune reaction to a medication [1.7.1].

• Common Culprits: Frequently implicated drugs include antihypertensives (like ACE inhibitors and beta-blockers), NSAIDs, biologics (TNF-alpha inhibitors), and statins [1.2.1, 1.7.4].

• Variable Onset: The time between starting a drug and the appearance of LPP can range from weeks to over a year, complicating diagnosis [1.2.1].

• Diagnosis is Key: Diagnosis relies on a clinical exam, a thorough medication history, and often a scalp biopsy to confirm inflammation around the hair follicles [1.4.5, 1.6.1].

• Management Goal: The primary treatment is to stop the offending medication, if possible, which typically leads to resolution over weeks to months [1.7.5].

• Anti-inflammatory Treatment: Topical or injected steroids are first-line therapies to control scalp inflammation and prevent further scarring hair loss [1.5.2].

• Hair Loss is Permanent: The hair loss from LPP is scarring and permanent, so early intervention is critical to preserve existing hair [1.4.7].

Understanding Lichen Planopilaris and Drug-Induced Triggers

Lichen planopilaris (LPP) is an inflammatory condition that leads to permanent, scarring hair loss on the scalp [1.4.7]. It is considered an autoimmune disorder where the body's own immune cells, specifically T-lymphocytes, mistakenly attack the hair follicles [1.4.2, 1.4.3]. This attack destroys the stem cells needed for hair growth, replacing the follicle with scar tissue [1.4.7]. While the exact cause of LPP is often unknown, it can be triggered or mimicked by a reaction to certain medications. This is known as a lichenoid drug eruption [1.7.1].

A lichenoid drug eruption can appear clinically and histologically similar to idiopathic lichen planus, making a thorough medication history crucial for diagnosis [1.7.3]. The time between starting a medication and the onset of the eruption, known as the latent period, can vary significantly, from a few weeks to over a year, which can make identifying the specific cause challenging [1.2.1, 1.3.5].

Common Medications Implicated in Lichen Planopilaris

A wide variety of medications have been reported to cause lichenoid drug eruptions that can manifest as LPP. It's important to note that while an association exists, it doesn't mean everyone who takes these drugs will develop the condition. The reaction often depends on individual factors and immune response [1.3.3].

Major Drug Classes Associated with LPP:

• Antihypertensives: This is one of the most frequently cited categories. Drugs used to treat high blood pressure, such as ACE inhibitors, beta-blockers, thiazide diuretics (like hydrochlorothiazide), methyldopa, and nifedipine, are commonly implicated [1.2.1, 1.4.1, 1.6.6].
• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Commonly used for pain and inflammation, NSAIDs are a known trigger [1.2.1, 1.2.4].
• Antimalarials: Drugs like hydroxychloroquine and chloroquine have been associated with lichenoid reactions [1.2.1, 1.3.3]. Ironically, hydroxychloroquine is also used as a treatment for LPP [1.5.2].
• Diuretics: Beyond just thiazides, other diuretics like furosemide and spironolactone have been reported as potential causes [1.2.1, 1.2.4].
• Biologics and Immunomodulators: Tumor necrosis factor (TNF)-alpha inhibitors such as infliximab, etanercept, and adalimumab are recognized triggers [1.2.1, 1.3.3]. Additionally, newer drugs like checkpoint inhibitors (CKIs) and tyrosine kinase inhibitors (TKIs) used in cancer therapy are increasingly reported as culprits [1.6.3, 1.6.4].
• Statins: Medications used to lower cholesterol, such as atorvastatin and simvastatin, have been linked to lichenoid drug eruptions [1.6.2, 1.7.4].
• Antimicrobials: Certain antibiotics (tetracyclines, isoniazid, ethambutol) and antifungal medications (ketoconazole) can induce these reactions [1.3.3]. Anti-tuberculosis treatments are a notable cause in some populations [1.6.1].
• Anticonvulsants: Medications for seizures like carbamazepine and phenytoin have been identified as potential triggers [1.2.1, 1.2.4].

Comparison of Common Drug Triggers

Drug Class	Common Examples	Primary Use	Latency Period
Antihypertensives	ACE inhibitors, Beta-blockers, Thiazides	High Blood Pressure	Weeks to Months [1.2.1]
NSAIDs	Ibuprofen, Naproxen	Pain, Inflammation	Can be as short as 2 weeks [1.6.1]
Biologics	Infliximab, Etanercept, Adalimumab	Autoimmune Diseases, Cancer	Average of 15.7 weeks [1.6.3]
Statins	Atorvastatin, Simvastatin	High Cholesterol	2 to 12 weeks [1.7.4]
Antimalarials	Hydroxychloroquine, Chloroquine	Malaria, Autoimmune Diseases	Weeks to Months [1.3.3]
Anti-tuberculosis drugs	Isoniazid, Rifampicin	Tuberculosis	1 to 7 months [1.6.1]

Diagnosis and Management of Drug-Induced LPP

Diagnosing drug-induced LPP involves a multi-step process.

Diagnostic Steps

1. Clinical Examination: A dermatologist will examine the scalp for signs of inflammation, redness around hair follicles, and scarring patches of hair loss [1.4.7]. A dermoscopy (trichoscopy) may be used to get a magnified view [1.4.5].
2. Medication Review: A detailed history of all medications, including over-the-counter drugs and supplements, is essential. The timing of when a new medication was started in relation to the onset of hair loss is a critical clue [1.6.1].
3. Scalp Biopsy: A small skin sample is taken from the affected scalp area for histopathological analysis. In a lichenoid drug reaction, the biopsy often shows a band-like inflammatory infiltrate and may contain eosinophils, which can help distinguish it from idiopathic LPP [1.4.3, 1.7.4].
4. Dechallenge/Rechallenge: The gold standard for confirming a drug-induced reaction is to stop the suspected medication (dechallenge) and observe for improvement. The eruption should resolve within weeks to months after discontinuation [1.7.5]. In some cases, reintroducing the drug (rechallenge) may be done under medical supervision to confirm the cause, but this is not always practical or safe [1.6.1].

Management Strategies

The primary goal of treatment is to stop the inflammation and prevent further permanent hair loss [1.4.2].

• Discontinuation of the Offending Drug: The most crucial step is to identify and stop the medication causing the reaction, if medically possible [1.7.5]. Resolution can take weeks or months [1.5.5].
• Topical Treatments: High-potency topical corticosteroids (e.g., clobetasol) are often the first-line treatment to reduce inflammation directly on the scalp [1.5.2]. Topical calcineurin inhibitors like tacrolimus are another option [1.5.1].
• Intralesional Steroids: Injecting corticosteroids like triamcinolone acetonide directly into the inflamed areas of the scalp can be effective for localized disease [1.5.2].
• Systemic Medications: If the condition is severe or widespread, oral medications may be necessary. These can include oral corticosteroids (like prednisone) for short-term control, or longer-term options like hydroxychloroquine, methotrexate, or mycophenolate mofetil [1.5.1, 1.5.4].

Conclusion

Drug-induced lichen planopilaris is a significant potential side effect of a wide range of common medications. From blood pressure pills and NSAIDs to modern biologics, many drugs can trigger the autoimmune reaction that leads to this form of scarring alopecia. Early diagnosis through careful medication history and scalp biopsy is vital. The cornerstone of management is identifying and discontinuing the culprit drug, followed by anti-inflammatory treatments to halt the progression of hair loss and preserve remaining hair follicles. Patients experiencing unexplained hair loss, particularly after starting a new medication, should consult a dermatologist promptly. Find a dermatologist

Frequently Asked Questions

Can blood pressure medication cause lichen planopilaris?

Yes, several types of high blood pressure medications are commonly associated with lichenoid drug eruptions that can cause lichen planopilaris. These include ACE inhibitors, beta-blockers, and thiazide diuretics [1.2.1, 1.4.1].

Is hair loss from drug-induced LPP reversible?

No, the hair loss from lichen planopilaris is scarring and therefore permanent because the hair follicle is destroyed and replaced with scar tissue. Treatment aims to stop the progression of the disease and save the remaining hair [1.4.7].

How long after stopping a drug will LPP improve?

After discontinuing the trigger medication, the rash and inflammation should improve, but it can take several weeks to months for the condition to fully resolve [1.7.5].

What is the most common class of drugs to cause lichenoid reactions?

Studies have shown that antihypertensive medications are one of the most common culprits [1.6.6]. However, with the rise of new treatments, cancer therapies like checkpoint inhibitors and tyrosine kinase inhibitors are also becoming frequently reported causes [1.6.3].

How is drug-induced LPP diagnosed?

Diagnosis is made through a combination of a physical scalp examination, a detailed review of your medication history, and a scalp biopsy to look for specific inflammatory patterns. Stopping the suspected drug and seeing improvement helps confirm the diagnosis [1.6.1].

Can statins for cholesterol cause this type of hair loss?

Yes, statins (HMG-CoA reductase inhibitors) like atorvastatin and simvastatin have been reported to cause lichenoid drug eruptions, which can lead to LPP [1.7.4].

Are there treatments for LPP if I can't stop the medication?

Yes, if the causative drug is essential, dermatologists may manage the LPP with treatments aimed at reducing inflammation. These include potent topical steroids, intralesional steroid injections, or systemic immunosuppressive drugs to control the reaction while you continue the necessary medication [1.7.5, 1.5.2].