Background: Nonspecific hyper-reactive inflammatory response is an important feature of Behcet’s disease (BD), but the underlying mechanism has yet to be identified. Ultraviolet B (UVB)-induced erythema is a well-established experimental method for the investigation of antigen-independent cutaneous inflammation, and no data are available on UVB response in BD patients. Aim: To investigate the UVB-induced erythema by determining the minimal erythema dose in BD patients and matched healthy controls, and also to compare the results of UVB response with the skin pathergy reaction. Patients & methods: The study group consisted of 47 patients with BD, 32 with various rheumatic diseases and 21 healthy volunteers. UVM-57 (Ultraviolet Products, Cambridge, UK; 302 nm), was used as the narrow-band UVB source. The forearm of each individual was exposed to a 0.14–10.45 J/cm2 dose of 302-nm UVB with 0.045 J/cm2 increments. The skin pathergy reaction was tested using a 20 G hypodermic needle as previously described. The...