o A viral infection or streptococcal pharyngitis are the usual triggering event. Other possibilities include other bacterial infections,food,drug,chemical toxins,and lumphoma.Phenacetin,tetracycline, erythromycin,quinidine,and insect bites have all been incriminated. ⚫ A viral infection or streptococcal pharyngitis are the usual triggering event. Other possibilities include other bacterial infections, food, drug, chemical toxins, and lumphoma. Phenacetin, tetracycline, erythromycin, quinidine, and insect bites have all been incriminated