Anaphylactic shock: no time to think

Anaphylaxis is the quintessential medical emergency where prompt recognition and treatment is life-saving. In the UK the incidence is increasing year on year, and is most common in the sixth and seventh decades of life. More than half of cases are iatrogenic in nature, most of the rest are caused by venom (stings) and food substances. The clinical signs can be subtle, but an acute onset of skin or mucosal oedema with respiratory compromise or reduced blood pressure should alert the physician to the diagnosis. The management revolves around the use of adrenaline after an initial airway, breathing and circulation approach, in a dose of 0.5 mg 1:1,000 intramuscularly, repeated five minutes later if there has been no response. Any delay in treatment is associated with increased risk of adverse outcome. Steroids and antihistamines are often given, although there is no convincing evidence of their effect in the acute setting. Where diagnostic uncertainty arises, serum tryptase levels can confirm or refute the diagnosis.