“…One such stimulus may be drugs, including antifolate agents (methotrexate and pemethrexate), 26,27 antidepressants (paroxetine and fluoxetine), 28,29 appetite suppressants, 30 infliximab, 31 procainamide, 32 cimetidine, 33 sulfamethoxazole-trimethoprime, 34 and other substances (herbs, cocaine, bacillus Calmette-Guérin vaccine, and formaldehyde). [35][36][37][38] Moreover, rare cases induced or exacerbated by physical stimuli have been reported, including sun or ultraviolet light exposure, 39,40 cold, 41,42 and physical exercise. 43 In some UV patients, a collagen-like region of the complement fragment C1q has been implicated as the target antigen.…”