Inclusion Criteria:  Age group above 18 years old Patients of both genders Classic type of cutaneous LP.  Exclusion criteria:  Topical treatment for LP 2 weeks before enrollment in the study or systemic treatment for LP 4 weeks before enrollment in the study and 3 years for systemic retenoids. Actinic LP , LP pigmentosus and Mucosal only LP Drug induced lichenoid eruption Conditions precluding taking skin biopsy : bleeding tendency , lidocaine allergy PD-1 associated-diseases e.g.: SLE, Cancers including melanoma and non-melanoma skin cancers, and Bullous Pemphigoid