ESSENTIALS OF DIAGNOSIS
Recurrent, painful oral and genital aphthous ulcers.
Erythema nodosum–like lesions; follicular rash; pathergy phenomenon.
Anterior or posterior uveitis. Posterior uveitis may be asymptomatic until significant damage to the retina has occurred.
Neurologic lesions can mimic multiple sclerosis.
Named after the Turkish dermatologist who first described it, Behçet disease is of unknown cause and most commonly occurs in persons of Asian, Turkish, or Middle Eastern background. The protean manifestations are believed to result from vasculitis that may involve all types of blood vessels: small, medium, and large, on both the arterial and venous side of the circulation.
The hallmark of Behçet disease is painful aphthous ulcerations in the mouth. These lesions, which usually are multiple, may be found on the tongue, gums, and inner surfaces of the oral cavity (eFigure 20–29). Genital lesions, similar in appearance, are also common but do not occur in all patients. Other cutaneous lesions of Behçet disease include tender, erythematous, papular lesions that resemble erythema nodosum. On biopsy, however, many of these lesions are shown to be secondary to vasculitis rather than septal panniculitis. These erythema nodosum–like lesions have a tendency to ulcerate, which is a major difference between the lesions of Behçet disease and the erythema nodosum seen in sarcoidosis and inflammatory bowel disease. An erythematous follicular rash that occurs frequently on the upper extremities may be a subtle feature of the disease. The pathergy phenomenon is frequently underappreciated (unless the patient is asked); in this phenomenon, sterile pustules develop at sites where needles have been inserted into the skin (eg, for phlebotomy).
Behçet syndrome characterized by recurrent oral and genital ulcers in a 17-year-old girl. (Used, with permission, from Richard P. Usatine, MD, in Usatine RP, Smith MA, Mayeaux EJ Jr, Chumley HS. The Color Atlas and Synopsis of Family Medicine, 3rd ed. McGraw Hill, 2019.)
A nonerosive arthritis occurs in about two-thirds of patients, most commonly affecting the knees and ankles. Eye involvement may be one of the most devastating complications of Behçet disease. Posterior uveitis, in essence a retinal venulitis, may lead to the insidious destruction of large areas of the retina before the patient becomes aware of visual problems. Anterior uveitis, associated with the triad of photophobia, blurred vision, and a red eye, is intensely symptomatic. This complication may lead to a hypopyon, the accumulation of pus in the anterior chamber (eFigure 20–30). If not treated properly with mydriatic agents to dilate the pupil and corticosteroid eyedrops to diminish inflammation, the anterior uveitis may lead to synechial formation between the iris and lens, resulting in permanent pupillary distortion.
Severe uveitis with hypopyon. (Used, with permission, from Vaughan DG, Asbury T, ...