Bullous systemic lupus erythematosus associated with KikuchiFujimoto disease : a case report as a diagnostic challenge

Bullous lupus is a rare systemic dermatosis, which is caused by antibodies against type VII collagen of the dermoepidermal junction. Although rarely, Kikuchi-Fujimoto disease can be associated with lupus and it is a histiocytic necrotizing lymphadenitis. Man, 22 years, presenting vesicolobullous lesions on the oral and genital mucosa, abdomen, buttocks, armpits and painful lymphadenomegaly, bicytopenia, proteinuria, ANF considerably positive and serositis. Skin histopathology was compatible with dermatitis herpetiformis, but direct immunofluorescence showed an IgG and IgA linear pattern on the basal membrane zone. Lymph node biopsy showed a CD8+ and CD68+ linfohistiocytic infiltrate surrounding a coagulative necrosis zone. Those clinical findings allowed the diagnosis of bullous lupus with Kikuchi-Fujimoto disease and the patient had a satisfactory response to the therapy.O lúpus bolhoso é uma dermatose sistêmica rara, decorrente da presença de anticorpos contra o colágeno tipo VII da junção dermo-epidérmica. A doença de Kikuchi-Fujimoto pode se associar, embora raramente, ao lúpus e caracteriza-se por uma linfangite histiocitária necrotizante. Paciente masculino, 22 anos, com lesões vésico-bolhosas orais, no abdome, nádegas e axilas, além de adenomegalias dolorosas, bicitopenia, proteinúria, FAN fortemente positivo e serosites. O anatomopatológico sugeriu dermatite herpetiforme, mas a imunofluorescência direta revelou depósito linear de IgG e IgA na zona de membrana basal. A biópsia de linfonodo mostrou infiltrado linfohistiocitário CD8+ e CD68+ com necrose coagulativa. Os achados permitiram o diagnóstico de lúpus bolhoso associado à doença de Kikuchi-Fujimoto e o paciente respondeu satisfatoriamente ao tratamento empregado