Allergy
You can give blood if you have mild hay fever or another mild allergy to a food or environmental substance, as long as you are fit and well on the day, even if you are taking anti-histamines or using intra-nasal steroids such as beclometasone (Beconase).
You can give blood if you are allergic to nickel.
You cannot give blood for one year after a reaction to a medicine/medication.
You cannot give blood if you have ever had anaphylaxis or if you carry adrenaline/epinephrine (Anapen or EpiPen) for self administration.
You cannot give blood for 7 days after taking oral steroid tablets or prescribed steroid injections.
You cannot give blood if you have an acute allergic reaction at present, until your symptoms have settled and a further deferral period (weeks to months) may be necessary depending on the severity of the attack.