This case study illustrates the effectiveness of dietary advice in a y
oung boy with chronic idiopathic urticaria. An azo dye and preservativ
e-free diet was initially advised, resulting in a total improvement in
urticarial symptoms. Double-blind challenges confirmed the boy was in
tolerant to E127 (erythrosine), E122 (carmoisine), 128 (red 2G), and E
102 (tartrazine) but not to E211 (sodium benzoate).