Case Report
A 20-year-old female was referred to our clinic with generalized reticular pruritic erythematous-violaceous eruption. The lesions had appeared during the first year of life on her chest and gradually progressed to the other parts. Repeated courses of topical corticosteroids had been administered without any significant improvement. Her past medical and family history was unremarkable. Examination revealed keratotic violaceous papules arranged in a reticular pattern with symmetrical distribution over the extremities and trunk (Figure 1). The lesions were more confluent on the lateral trunk, breasts, buttocks, and extremities. The individual lesions were erythematous verrucous papules covered by a hyperkeratotic plug that could be removed with difficulty.
There was an erythematous rosacea-like eruption on her face. The neck was involved circumferentially and the scalp was scaly but scalp hair, eyebrows, and eyelashes had a normal thickness and density. The nails were dystrophic and greatly thickened and there were many keratotic papules on the palmoplantar surfaces. She had tender erosions on her tongue along with soreness sensation in her oral mucosa. Examination of the other mucosal sites including genital mucosa and conjunctiva was insignificant. There were no signs of internal organ involvement or lymphadenopathy.
Routine laboratory data including complete blood count, ESR, CRP, liver, and renal function tests were normal.
We performed skin biopsy with differential diagnoses of KLC, psoriasis, hypertrophic lichen planus, and pityriasis rubra pilaris. Histologic examination of the skin specimen revealed variable epidermal thickening and areas of acanthosis and atrophy, hyperkeratosis, focal parakeratosis with remnants of neutrophils, lichenoid interface reaction with band-like sub-epidermal infiltration of lymphocytes and a few plasma cells which were compatible with keratosis lichenoides chronica (Figure 2).
The diagnosis of KLC was considered based on typical clinical and histopathologic findings and the patient was started in acitretin 25 mg/daily. This led to gradual improvement of the skin lesions with prominent papular flattening and erythema reduction 3 months after treatment commenced but her oral lesions did not demonstrate any significant improvement.