From the Guidelines
Sudden lichen planus is most commonly caused by immunotherapy-related toxicities, particularly in patients receiving ICI treatment, with a mean time to onset of approximately 6 to 12 weeks after initiation of treatment. This condition is characterized by violaceous papules and plaques without scale over the trunk and extremities, and significant pruritus, as reported in the 2024 NCCN guidelines 1. The exact trigger for lichen planus in the general population is often unknown, but several factors can precipitate this autoimmune reaction, including medications, viral infections, stress, genetic predisposition, and environmental factors. However, in the context of immunotherapy, ICI-related lichen planus and lichenoid disease have been reported to occur in up to 6% of patients who received ICI treatment 1.
Key Factors Contributing to Sudden Lichen Planus
- Immunotherapy-related toxicities, particularly ICI treatment, as evidenced by the 2024 NCCN guidelines 1
- Medications, such as beta-blockers, antimalarials, NSAIDs, and certain antibiotics
- Viral infections, particularly hepatitis C
- Stress, which can trigger or worsen outbreaks in susceptible individuals
- Genetic predisposition, as lichen planus occasionally runs in families
- Environmental factors, like exposure to certain chemicals or allergens
Management and Treatment
Treatment of sudden lichen planus depends on identifying and removing potential triggers while managing symptoms. According to the 2024 NCCN guidelines, topical steroids are the most frequently used treatments for the management of lichenoid dermatitis, with other treatments including oral antihistamines, oral steroids, acitretin, intralesional triamcinolone, narrow-band UVB, and other unspecified nonsteroidal treatments 1. In severe cases, systemic medications like oral corticosteroids or immunosuppressants may be necessary. The most effective treatment approach should be guided by the underlying cause of the lichen planus, with a focus on managing symptoms and preventing further outbreaks.
From the Research
Causes of Sudden Lichen Planus
- The etiology of lichen planus is still unknown, but some external and internal factors have been suggested to trigger the disease, including drugs, stress, and hepatitis C virus 2.
- Various drugs, such as beta-blockers, methyldopa, penicillamine, quinidine, and quinine, have been implicated in the cause of lichen planus 3.
- Nonsteroidal antiinflammatory agents may also be considered causative of lichen planus, based on available epidemiologic evidence 3.
- Altered self-antigens on the surface of basal keratinocytes, modified by viruses or drugs, are believed to be the targets of the T-cell response in lichen planus 2.
- Contact allergens, such as amalgam, may cause lichenoid reactions, which are the main differential diagnoses of lichen planus 2.
Triggers of Lichen Planus
- Drugs, including beta-blockers, methyldopa, penicillamine, quinidine, and quinine, have been reported to trigger lichen planus 3.
- Stress may also be a trigger for lichen planus, although the exact mechanism is not well understood 2.
- Hepatitis C virus has been suggested as a potential trigger for lichen planus, although the relationship between the two is not fully understood 2.
- Other potential triggers, such as nonsteroidal antiinflammatory agents, have been suggested, but the evidence is not as strong 3.