The most typical form of lichen planus can be described by the “six Ps”: purple, pruritic, polygonal, planar, papules, and plaques.
Lichen planus is an inflammatory condition that commonly affects the skin but may also involve the oral mucosa, genital mucosa, nails, and scalp. Its distribution is typically symmetric and distributed along the wrists, flexural aspects of the arms and legs, and the lower back. They often develop along areas of trauma (Koebner’s phenomenon).
The etiology is unknown but there appears to be an increased incidence in patients with hepatitis C. Several drugs can cause lichenoid eruptions. Thus, a reconciliation of recent medications must be performed in suspected cases. The table below lists several drugs implicated in such reactions. The bolded drugs are the ones most frequently implicated.
|Group of drug|
|Antimicrobial substances||Aminosalicylate sodium, ethambutol, griseofulvin, ketoconazole, streptomycin, tetracycline, trovafloxacin, isoniazid|
|Antihistamines (H2-blocker)||Ranitidine, roxatidine|
|Antihypertensives/antiarrhythmics||ACE-inhibitors (captopril, enalapril), doxazosin, beta blockers (propranolol, labetalol, sotalol), methyldopa, prazosin, nifedipine, quinidine|
|Antimalarial drugs||Chloroquine, hydroxychloroquine, quinine|
|Antidepressives/antianxiety drugs/antipsychotics/anticonvulsants||Amitriptyline, carbamazepine, chlorpromazine, levomepromazine, methopromazine, imipramine, lorazepam, phenytoin|
|Diuretics||Thiazide diuretics (chlorothiazide and hydrochlorothiazide), furosemide, spironolactone|
|Antidiabetics||Sulfonylureas (chlorpropamide, glimepiride, tolazamide, tolbutamide, glyburide)|
|Metals||Gold salts, arsenic, bismuth, mercury, palladium, lithium|
|Nonsteroidal-antiinflammatory drugs (NSAIDs)||Acetylsalicylic acid, benoxaprofen, diflunisal, fenclofenac, flurbiprofen, ibuprofen, indomethacin, naproxen, sulindac|
|Proton pump inhibitors||Omeprazole, lansoprazole, pantoprazole|
|Lipid lowering drugs||Pravastatin, simvastatin, gemfibrozil|
|Tumor necrosis factor-alpha antagonists||Infliximab, adalimumab, etanercept, lenercept|
|Varia||Allopurinol, bleomycin, cinnarizine, cyanamide, dapsone, hydroxyurea, hepatitis B-vaccine, imatinib, immunoglobulins, interferon alfa, l-thyroxin, levamisole, mesalamine, methycran, penicillamine, procainamide, pyrimethamine, pyrithioxine, quinacrine, sildenafil, sulfasalazine, terbinafine, trihexyphenidyl, ursodeoxycholic acid|
It is diagnosed by its characteristic appearance as above “the six Ps” and by biopsy if clarification is needed. The differential diagnosis includes: eczema, lichen simplex chronicus, pityriasis rosea, prurigo nodularis, psoriasis, and syphilis,
Treatment options lack large randomized controlled trials to support practice. However, potent topical corticosteroids are often used early for localized lesions. Systemic oral corticosteroidscan be used for more generalized lesions.
Am Fam Physician. 2011 Jul 1;84(1):53-60.
Am Fam Physician. 2000 Jun 1;61(11):3319-3324.