Comparisons between the allele frequencies in patients and controls showed a positive association with cutaneous idiopathic lichen planus for the DRB1*0101 allele (RR = 5.8, P = 0.0097), DRB1*0101 and DRB1*0102 are associated with the same DQA1 and DQB1 alleles and are different only for two amino acids in positions 85 and 86 of the DRB1 gene.