Purpuric Variant of Keratosis Lichenoides Chronica

Keratosis lichenoides chronica or nekam disease is a rare dermatosis of unknown etiology. It is characterized by linear and reticulate lesions of lichenoid appearance, scaly plaques, and keratotic papules on the trunk and limbs. In addition to these 3 characteristic features, there may also be an eruption on seborrheic areas of the face. This clinical variability, the numerous confusing names given since Kaposi’s first description in 1895,1 and the nonspecific histological findings (“lichenoid pattern”) have contributed to the underdiagnosis of this disease. We report a case of keratosis lichenoides chronica in which we observed a marked purpuric component both clinically and histologically, in addition to the usual findings described. The patient was a 68-year-old man on treatment with omeprazole for hiatus hernia. he consulted for a 2-year history of pruritic skin eruption, for which he had received no previous treatment. The lesions had first appeared on both sides of the chest and had progressively spread over the entire trunk and extensor surfaces of the limbs. A few isolated papules had resolved spontaneously with no residual pigmentation. Physical examination revealed purpuric, lichenoid papules that coalesced into scaly, retiform plaques, located on the extensor surfaces of the lower legs and thighs, trunk, elbows, and on the backs of both hands (Figure 1). Follicular keratotic papules with a violaceous erythematous color were also observed on the knees, thighs, and elbows (Figure 2). There were scaly purpuric macules in the interdigital spaces of both hands, and several nail plates were dystrophic (thickened and yellowish). The head and neck region, palms, soles, and mucosas were unaffected. The complete blood count showed mild leukopenia (3×1000/mL) and the patient was referred to the hematology department, where hematological disease was ruled out at the time. Biochemical tests only revealed hypercholesterolemia (270 mg/dL). The other test results (coagulation studies, thyrotropin, vitamin B12, folic acid, hepatitis B and C serology, erythrocyte sedimentation rate, rheumatoid factor, and antinuclear antibodies) were normal or negative. Biopsies of 2 keratotic papules (left knee and thigh) revealed hyperkeratosis with focal parakeratosis. The superficial dermis presented a band-like inflammatory infiltrate formed of lymphocytes, histiocytes, and few plasma cells, with spongiotic degeneration of the basal layer and some colloid bodies. There were extravasated red blood cells at the dermal-epidermal junction and variable amounts of hemosiderin in the cytoplasm of the macrophages (Figure 3). Acitretin 25 mg/d was prescribed for 3 months, resulting in a slight improvement of the hyperkeratotic lesions but with no change in the scaly plaques or the purpuric component; the treatment was therefore withdrawn. The patient refused UV-A therapy, and the lesions have remained stable during subsequent follow-up. Although keratosis lichenoides chronica was first described by Kaposi in 1895 as “lichen ruber acuminatus verrucosus et reticularis”, the term now used was coined by Margolis in 1972. The varied nomenclature used has progressively added more confusion to the diagnosis of this disease, in itself clinically heterogenous.1 Keratosis lichenoides chronica is a rare dermatosis, considered by some authors as a variant of lichen ruber planus, due to its histological lichenoid features.2 Although scaly erythematous plaques, lichenoid papules, and follicular plugs are characteristic findings, other types Figure 1 Scaly erythematous plaques with a reticulate pattern are observed on the leg, together with keratotic papules.