Necrotizing fasciitis associated with systemic lupus erythematosus in a child

Abstract

Sir, Necrotizing fasciitis (NF) is a rapidly progressive, potentially fatal necrotizing infection of skin and subcutaneous tissues.[1] It is rarely seen in children and its association with systemic lupus erythematosus (SLE) is even rarer. We report a 11-year-old female child who developed NF of the lower leg and was incidentally diagnosed to have SLE. Patients with SLE are predisposed to develop fatal infections. Early recognition of this condition and its association is important to prevent mortality. A 11-year-old female child was referred from the pediatric intensive care unit for evaluation of painful skin lesions on her left lower limb since two weeks. There was a history of local trauma following which the child developed swelling and pain of her left lower limb associated with fever. She was diagnosed to have cellulitis and treated with intravenous antibiotics ceftriaxone, amikacin, and metrogyl with not much improvement. Past history was noncontributory. Cutaneous examination revealed ill-defined ecchymotic plaque with overlying bullae on the medial aspect of left lower leg [Figure 1]. The entire limb was edematous and tender with local increase in temperature. Over one day, the lesions blackened with areas of necrosis and yellowish slough involving the entire lower limb. In few days, there was necrosis extending into deeper planes of skin. Laboratory investigations showed anemia (hemoglobin: 6.2 mg%), leukopenia (2500 cells/mm3), thrombocytopenia (32,500 cells/mm3), increased liver enzymes, and hyponatremia. Urine routine test showed hematuria and proteinuria. Erythrocyte sedimentation rate (ESR) and C-reactive protein were highly elevated. Chest radiography and ultrasonogram abdomen were normal. Serology for Human immunodeficiency virus (HIV) and blood culture was negative. Culture from the tissue and pus grew group A Streptococcus, Klebsiella, and Escherichia coli. A diagnosis of NF was considered. In view of the above clinical features and investigations, antinuclear antibody and anti-double-stranded DNA tests were done, which were strongly positive. A final diagnosis of systemic lupus erythematosus with NF was made. Surgical debridement of necrotic tissue was done [Figure 2]. As the necrosis had reached the bony tissues, amputation was done. However, the child died due to sepsis. Figure 1 Ecchymotic plaque with overlying bullae and necrotic areas on the medial aspect of left lower leg Figure 2 Surgical debridement showing necrotic tissue extending into deeper planes NF is a life-threatening infection with a high mortality rate ranging from 20% to 80% despite the use of appropriate treatment modalities. The etiology of NF is polymicrobial in nature. Most patients with NF have associated comorbidities such as diabetes, HIV infection, renal failure that predispose them to infections.[2] Clinically the patient presents with ecchymosis, bullae, necrosis, and gangrene. The inflammation rapidly progress to involve deep fascial planes thus making the importance of early diagnosis and exploration. Infections are the major cause of mortality in SLE. Even though SLE patients are prone to develop infections, NF is rarely reported. There is an increased risk of infections in SLE due to impaired cell-mediated immunity, immunoglobulin deficiencies, complement factor deficiency, and various defects in other immune effector cells, including neutrophils, macrophages, and natural killer cell.[3] Genetic predisposition and presence of R131variant of FCrRIIA on Fc receptor are believed to contribute to the risk of infection.[4] NF has been associated with other rheumatic disorders that include dermatomyositis, polymyositis, systemic sclerosis, rheumatoid arthritis, and ankylosing spondylitis.[5] Clinically, NF may not be diagnosed early and only when necrosis occurs diagnosis may become evident. In our case, the child had been diagnosed as having soft tissue infection before presenting to us and treated with antibiotics, which were unresponsive. This indicated deeper infection that required aggressive approach and exploration. Even though appropriate interventions and surgical debridement was done, as the child had presented to us late, there was a delay in diagnosis; the child had to undergo amputation and eventually succumbed to sepsis. There is partly increased risk of infections due to use of oral steroids and immunosuppressants in SLE cases but our case was treatment naïve and it was SLE-associated immunosuppression that must have contributed to the infection. Impaired immune response in SLE is a primary risk factor for developing NF which is an emergency condition requiring early detection and quick debridement. Increased awareness of this condition and its association is necessary to prevent mortality.