Serious adverse reactions to adrenaline are becoming more likely

EDITOR,—Pamela W Ewan's findings with regard to peanut and nut allergy1 agree with my personal experience of the problem: such allergy occurs in otherwise atopic subjects, it is acquired early (possibly in utero in some cases), and after the first adverse reaction sufferers are almost invariably aware of the problem—although in some this is at a subconscious level, and they become averse to all nuts without remembering the reason.

I doubt, however, Ewan's implication that the problem is becoming much more common. It is difficult to obtain meaningful figures of prevalence in the past, but I have estimated a probable prevalence of hypersensitivity to any nut of between 1% and 5% in the population from which my patients have been drawn over some 30 years, and without much variation. Previously, those affected knew that they could not eat nuts, avoided them assiduously, were generally free of symptoms, and did not consult a doctor, which explains the medical profession's lack of awareness of the problem in the past. Those affected were detected, if at all, when they attended allergy clinics for investigation of other manifestations of atopy. Now, on the other hand, as a consequence of publicity generated by such organisations as the Anaphylaxis Campaign and British Allergy Foundation,2 many people who managed very well by themselves over many years have been informed that they must seek medical advice and be referred to clinics, where investigation confirms only what they know already.

A consequence of this is that we are seeing a true increase in serious adverse reactions to adrenaline injections, which are now being offered routinely to such patients and used for any symptoms, whether trivial or even unrelated to hypersensitivity. Parenteral adrenaline certainly plays a major part in the management of dangerous anaphylaxis and angio-oedema, but these are exceedingly rare (especially when one considers the high prevalence of sensitivity to nuts), and they probably usually involve additional, non-atopic factors. Avoidance remains the golden rule and is usually practised successfully because the patient's tongue and lips are aware of traces of the allergen in prepared foods to which the patient has been blinded. Better labelling of foods would help, but I fear that we may see more frequent dangerous episodes, including deaths, due to adrenaline than to anaphylaxis unless a more measured response to the problem is developed.