Anaphylaxis is an acute serious allergic reaction, with multi-organ system manifestations caused by the release of chemical mediators and it is potentially fatal . Between 5% and 14% of patients may experience a recurrence of anaphylaxis 8-12 hours after the initial presentation, called biphasic (late-phase) . The mainstay of treatment for children experiencing anaphylaxis remains adrenaline and H1-antihistamines. Corticosteroids are not life-saving and do not have an immediate effect on the symptoms of anaphylaxis but may help reduce or prevent a biphasic late phase reaction . The aim of this study is to compare the efficacy of oral glucocorticoids in prevention of the second phase or biphasic reaction of anaphylaxis, as compared to placebo in children, presenting to the pediatric emergency department (PEC Al-Sadd) with mild to moderate anaphylaxis (Prospective Study). Patients will be randomized to either one of the two treatment: Treatment 1: Dexamethasone 0.6mg/kg oral. Treatment 2 : Placebo All patients will be urgently treated for anaphylaxis according to guideline protocol. Enrolled patients will be given one of the study medications orally, and he /she will observe in the observation room with cardiac monitor and close monitoring by nurse. The treating physician will discharge patient when he/she looks well, breathing comfortably, has oxygen saturation \>94%, stable blood pressure and no gastrointestinal or neurological manifestation. Discharge patients will be sent home on anti-histamine (cetirizine) for 5days. All patients will be followed up for one week post discharge by a phone call asking about the general condition, relapse of symptoms, or need for readmission.