A case of Behçet's disease associated with necrotizing small vessel vasculitis

Behçet Disease: An Update for Dermatologists

Behçet disease (BD) is a chronic, relapsing, systemic vasculitis of unknown etiology with the clinical features of oral and genital ulcers, cutaneous vasculitic lesions, ocular, articular, vascular, gastrointestinal, neurologic, urogenital and cardiac involvement. BD usually appears around the third or fourth decade of life. Gender distribution is roughly equal. The disease is much more frequent in populations along the ancient 'Silk Road', extending from Eastern Asia to countries in the Middle East and the Mediterranean, compared with Western countries, but has universal distribution. Mucocutaneous manifestations are the clinical hallmarks of BD. The diagnostic criteria widely used in the disease's diagnosis are based on mucocutaneous manifestations because of their high sensitivity and/or specificity. Genetic factors are the key driver of BD pathogenesis, and HLA-B51 antigen is the strongest genetic susceptibility factor. Streptococcus sanguinis (S. sanguinis) or microbiome change can trigger innate immune system-mediated inflammation sustained by adaptive immune responses. Epistatic interaction between HLA-B51 and endoplasmic reticulum aminopeptidase 1 (ERAP1) in antigen-presenting cells disrupt T-cell homeostasis leading to downregulation of Tregs and expansion of Th1 and Th17. Thus, neutrophil activation and intense neutrophil infiltration of the affected organs develop in the early stage of inflammation. BD has a variable clinical course with unpredictable exacerbations and remissions. The disease is associated with a high mortality rate, especially in young male patients, and large-vessel, neurological, gastrointestinal system and cardiac involvement are the most important causes of death. The principal aim of treatment should be to prevent irreversible organ damage, especially during the disease's early, active phase. A better understanding of the disease's pathogenesis has provided important information on its management. New drugs, especially apremilast and anti-TNF-α agents are effective in the management of BD and have the potential to improve patients' quality of life, prognosis and survival.

Tuberculous lymphadenitis and the appearance of Behçet's disease-like symptoms

A 48-year-old man visited our hospital complaining of a tender mass in the left side of the neck. He was diagnosed with tuberculous lymphadenitis based on the results of a biopsy. Shortly after the diagnosis, oral aphthae, erythema nodosum-like lesions on the lower legs and genital ulcers developed. A diagnosis of cutaneous tuberculosis was ruled out according to a negative mycobacterial culture of tissues obtained from stained smears and lesional biopsy specimens. The patient's symptoms remitted following the introduction of antituberculous therapy. We assume that tuberculous lymphadenitis was strongly associated with the appearance of Behçet's disease-like symptoms in this case.

[Cutaneous necrotizing vasculitis in a patient with Behcet's disease; mimicking polyarteritis nodosa]

A 25-year-old-man was referred with an approximately 1-year history of recurrent fever, tonsillitis, testicular pain and testicular swelling in June 2009. He also complained of visual disturbance, some erythema nodosum (EN) like lesions on his lower extremities and oral aphthous ulcerations for 5 months. Opthalmological consultation confirmed retinochoroiditis, and ultrasonography revealed epididymitis. A biopsy of the EN like lesion showed a necrotizing vasculitis of the small and medium-sized vessels with septal panniculitis in the subcutis. The laboratory findings revealed an elevation of CRP and positive HLA-B51. He was diagnosed with incomplete Behcet's disease according to the Japanese criteria (1987). After the initiation of the therapy with 10 mg/day of prednisolone, his symptoms promptly ameliorated. In our case, although epididymitis as well as the histopathological findings suggested polyarteritis nodosa (PN), a diagnosis of BD was established on the basis of other contemporaneous findings. Necrotizing vasculitis as a cutaneous manifestation in patients with BD has been rarely reported. However, BD and PN, including cutaneous PN, have rarely described in conjunction. Therefore, we propose that PN-like necrotizing vasculitis might be the subtype of BD.