Lichen Planus Pigmentosus Associated with Topical Olive Oil Application.

A 45-year-old brown-skinned woman presented with a 5-year history of asymptomatic grayish brown lesions on the face, arms, and legs. She had no medical history of previous diseases or contact dermatitis. She revealed that she had used olive oil all over her body for the last 8 years every other day. Physical examination showed multiple, well-defined, oval-shaped, dark brown, smooth-surfaced macules with no elevated active borders (Figure 1). There were no associated lesions on the nails, scalp, or mucosae. Serologic tests for autoantibodies and hepatitis A, B, and C virus infections were non-reactive. A patch test for olive oil was also negative. A skin biopsy revealed epidermal atrophy, orthokeratosis, basal cell vacuolation, and a band-like lymphocytic infiltrate in the upper portion of the dermis with abundant colloid bodies and pigmentary incontinence in the papillary dermis (Figure 2). A diagnosis of lichen planus pigmentosus (LPP) was confirmed, and betamethasone butyrate propionate was applied for 2 months over the lesions, with a limited therapeutic effect. Clinical improvement was seen only after she discontinued the olive oil application (Figure 3).