Lichen planus and liver diseases: a multicentre case-control study. Gruppo Italiano Studi Epidemiologici in Dermatologia (GISED).

OBJECTIVE--To assess the association of lichen planus with liver complaints and with known aetiological factors of liver diseases. DESIGN--Multicentre case-control study. Interviews were conducted by trained medical investigators on the basis of a structured questionnaire. At the interview patients and controls were asked for consent to blood samples being taken to determine transaminase activities and the presence of hepatitis B virus surface antigen. SETTING--Outpatient departments of 27 Italian general and teaching hospitals that were collaborating in the Gruppo Italiano Studi Epidemiologici in Dermatologia (GISED). SUBJECTS--Incident cases and controls were eligible. A total of 577 patients with lichen planus and 1031 controls with dermatological diseases other than lichen planus were interviewed. Less than 1% of the people contacted refused to participate. Patients and controls were matched for sex and age in five year intervals. RESULTS--The risk of lichen planus was higher in patients with a history of liver diseases requiring hospital admission or specialist consultation (relative risk = 1.6; 95% confidence interval = 1.2 to 2.2), those who had had liver biopsy (5.5; 1.9 to 15.6), and those with a history of viral hepatitis (1.9; 1.1 to 3.1). High activities of liver enzymes and positive results of tests for hepatitis B virus surface antigen were also associated with lichen planus. The association with alcohol consumption was not clearly confirmed by a dose-risk relation. CONCLUSION--This study adds quantitative epidemiological evidence to the clinical observation that liver disease is a risk factor for lichen planus although not a specific marker of it.