Coup-de Sabre is commonly associated with:

Systemic sclerosis Occasionally, the lesions occur as linear bands or ribbons on the face, particularly the forehead, on the chest and trunk or on an extremity. This has been termed linear scleroderma. Such a band, made up of a furrow with an elevated ridge on one side, is often termed a coup de sabre, since it resembles the mark produced by the blow of a sabre. The circumscribed lesions eventually become stiff and hard. It has been reported that facial hemiatrophy is associated with this form of the disease occurring in children. The lesions are generally asymptomatic, although pricking, tingling and itching sensations have been described. Reference: Shafer’s Textbook of ORAL PATHOLOGY Eighth Edition page no 563,564