Annular Lichen Planus in a Patient with Ulcerative Colitis: A Case Report of a Rare Morphological Variant Associated with Systemic Disease

Annular lichen planus (ALP) is a rare morphological variant of lichen planus that can mimic other annular dermatoses and often poses diagnostic challenges. Although lichen planus has been sporadically linked to systemic diseases, its association with ulcerative colitis is exceedingly rare. This case highlights the coexistence of ALP and ulcerative colitis, suggesting a possible immunopathogenic connection between the two conditions.

A 40-year-old woman with a three-year history of ulcerative colitis presented with a six-month history of intensely pruritic, violaceous, annular lesions affecting the dorsal feet, hands, wrists, and face. Examination revealed flat-topped papules, some forming plaques with Wickham striae and annular configurations. Histopathology confirmed the diagnosis of annular lichen planus. The patient had no other known triggers such as new medications, infections, or contact allergens. She was treated with topical corticosteroids and antihistamines, resulting in partial resolution of the lesions over a four-week period.

This case underscores the importance of considering systemic autoimmune diseases like ulcerative colitis in patients presenting with atypical forms of lichen planus. It adds to the limited literature documenting ALP as a possible cutaneous manifestation associated with inflammatory bowel disease.