“…A presumed viral illness has preceded the onset in 33% of cases including our own. [2][3][4]5,7,13,17,19,22,23,25,27,29,31,35,39,41,42 No consistent aetiological agent has been identified, but positive serology results have been reported for: herpes simplex virus (HSV), 11,13,26,34,35,41 varicella zoster virus (VZV), 2,5,11,13,21 tuberculoprotein, 1,5,34 antistreptolysin O, 4,13,39 Epstein-Barr virus, 25 CMV, 34 Coxsackie virus A10, 31 adenovirus, 34 measles 34 and rubella. 41 The cases listed in Table 1 and referred to above appear, with limited variation, to adhere to Ito's original description of a primary idiopathic FBA.…”