Anaphylaxis: the difficult diagnosis

The incidence of anaphylaxis is rising. The number of hospitalizations due to anaphylaxis has increased over the last couple of decades, with a threefold increase in England between 1994 and 2004 (Department of Health (DH), 2006).

The Resuscitation Council published revised and simplified guidelines on the emergency treatment of anaphylactic reactions in 2008. However, these guidelines highlighted that there is still confusion about the diagnosis, treatment, investigation and follow-up of patients who have an anaphylactic reaction (Resuscitation Council, 2008).

Anaphylaxis clearly poses challenges, not least because the lack of any consistent clinical manifestations continue to cause diagnostic difficulty. There is no universal agreement on how severe a reaction it must be to class it as ‘anaphylaxis’ as opposed to an allergic reaction.

Diagnostic skills are paramount in treating this time-critical condition, but the lack of a severity grading system has meant paramedics do not always correctly diagnose the extent of anaphylaxis (Resuscitation Council, 2008). A key challenge for paramedics appears to be when a patient is hovering between ‘severe allergy’, ‘anaphylaxis’ and a ‘life–threatening’ anaphylaxis. Each patient presents in a different way. Some may display all the symptoms in a textbook case, whereas others may have few symptoms (Brown, 2004).