Deep cutaneous lesions are seldom encountered in lupus erythematosus. The disease described in the literature as lupus erythematosus profundus or lupus erythematosus panniculitis usually occurs in middle-aged women. The authors report a case of deep lupus erythematosus which was exceptional in that it occurred in an 11-year old girl. The lesions were situated on the face and consisted of solid subcutaneous nodules and clear-cut ulcerations leaving atrophic pigmented scars. The histological image of a nodule was one of lobular lymphocytic panniculitis with homogeneous hyalinization of adipose nodules, to which must be added periadnexal and perivascular dermo-epidermal lymphocytic infiltrates. Granular IgM deposits arranged along the dermo-epidermal junction were observed at direct cutaneous immunofluorescence. Laboratory examinations showed leucopenia (3,300/mm3) with neutropenia (1,100/mm3) and the presence of antinuclear antibodies at 1/100 speckled fluorescence, as well as antibodies directed against native DNA. Studies of renal function and for complement gave normal results. The other causes of lobular panniculitis were excluded. The lesions regressed within 3 weeks under hydroxychloroquine; this drug was also successful in arresting a relapse consecutive to withdrawal of treatment. The authors have analysed the 17 paediatric cases of deep lupus erythematosus and were able to determine their main characteristics: 1. The lesions occur mostly in girls (70 p. 100). They are located electively on the face and the lateral aspect of the shoulders. They consist of well-limited, solid or hard subcutaneous nodule which may congregate to form plaques. The epidermis may be normal or pathological, poikilodermic, looking like a discoid or ulcerated lupus erythematosus. The lesions regress, leaving a characteristic atrophic scar.(ABSTRACT TRUNCATED AT 250 WORDS)