In this article we present a survey on the pathogenesis of allergic or pseudoallergic reactions in anaesthesia, the risk factors and the responsible substances. The incidence of anaphylactoid reactions is between 1:3500 and 1:20,000 anaesthetic cases. The estimated mortality rate amounts to 3-6%. Neuromuscular blocking drugs account for most of the cases of significant anaphylactoid reactions (59-70%). However, the incidence of latex-related reactions in increasing. Risk factors for anaphylaxis are a history of IgE-mediated drug allergy, repeated anaesthesias, atopy, hyperventilation tetany, and the use of neuromuscular blocking drugs in females. Risk factors for pseudoallergic reactions are emotional stress, atopic predisposition, increased sensitivity for histamin, hyperventilation tetany and female gender.

Eicosanoids partly develop from the metabolism of arachidonic acid through the cyclooxygenase or the lipoxygenase pathway. Lipoxygenase products are the leukotrienes (LTA4, LTB4, LTC4, LTD4, LTE4) and the 5-hydroxyeicosatetraenoic acid (5-HETE). Cyclooxygenase products are the prostanoids (prostaglandins [PG] D2, E2, F2, I2 and thromboxane A2). The other part of the eicosanoids develops from the metabolism of two other fatty acids over the same pathways; 8,11,14-eicosatrienoic acid leads to the prostaglandins D1, E1, F1, I1 and the leukotrienes A3, B3, C3, D3, E3. From 5,8,11,14,17-eicosapentaenoic acid result the prostaglandins D3, E3, F3, I3 and the leukotrienes A5, B5, C5, D5, E5. The pathophysiological changes in ARDS are mainly due to an imbalance of opposing effects of mediators. In this regard eicosanoids play an important role which has not yet been clearly determined. Bronchoconstriction and pulmonary hypertension are increased by thromboxane A2 and leukotrienes, whereas they are reduced by PGI2. Pulmonary edema is enlarged by leukotriene, especially, LTB4, whereas PGI2 has a protective effect. The aggregation of platelets is mediated through thromboxane A2, PGF2 and LTB4; PGE1 and PGI2 counteract these reactions. LTB4, in addition to 5-HETE, leads to the activation of inflammatory cells. Drug induced eicosanoid imbalances can be used for therapeutic interventions.

There is an increasing number of reports on anaphylactic reactions due to latex. We report on a 9-year-old boy who developed anaphylaxis shortly after induction of anaesthesia due to a combined latex and ethylene oxide allergy. Patients with multiple medical treatment and those with atopy seem to be at risk.

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