Causes, symptoms of anaphylaxis vary with age
“Specific causes of anaphylaxis, such as oral mite and galacto-oligosaccharide exposure, were unique in our Singaporean population. The recognition of age-related system involvement in anaphylaxis aids the allergist and emergency physician in diagnosis and acute management,” said researchers.
Researchers analysed 426 anaphylaxis patients (median age 23 years; 51 percent male), of whom 45 percent were children (n=191; 0–18 years) and 55 percent were adults (n=235; ≥19 years). Most of the cases (85 percent) had available information on the eliciting cause. [Int Arch Allergy Immunol 2018;175:91-98]
The most commonly reported trigger of anaphylaxis was food, which was reported in 55 percent (n=236) of the patients. This was followed distantly by drugs (7 percent; n=85) and insect bites (7 percent; n=28).
Food anaphylaxis was significantly more common in children than in adults (72 percent vs 42 percent; p<0.001), while drugs (28 percent vs 10 percent; p<0.001) and insect bites (11 percent vs 1 percent; p<0.001) were more frequent triggers in adults.
In terms of clinical presentation, majority of the cases (57 percent; n=243) involved two systems, while 35 percent and 8 percent of the cases involved three and four systems, respectively. The skin was involved in almost all of the anaphylaxis cases (98 percent; n=419). This was followed by the respiratory (81 percent; n=345) and cardiovascular (39 percent; n=165) systems.
Age-stratified analysis showed that gastrointestinal symptoms were significantly more common in infants and young children (adjusted odds ratio [OR], 2.1; 95 percent CI, 1.1–3.9). Adolescents and school children were significantly more likely to present with respiratory symptoms (adjusted OR, 2.7; 1.4–5.2).
In comparison, adults were more likely to have cardiovascular symptoms (adjusted OR, 2.9; 1.8–4) and hypotension (adjusted OR, 3.7; 2.1–6.8).
Intramuscular (92 percent; n=325) delivery of adrenaline (83 percent; n=352) was the most commonly employed acute treatment strategy. Other management options included inhaled bronchodilators (28 percent), intravenous fluids (41 percent), antihistamines (92 percent) and steroids (86 percent), of which the last two were consistently used regardless of age.
Moreover, clinical outcomes were good across all age groups, researchers noted. “Only seven patients required high dependency and intensive care admission. These patients consisted of four adults who required mechanical ventilation, of whom two had cardiovascular involvement, and three children who were admitted for observation of their cardiorespiratory status.”
None of the children transferred to intensive care required ventilation.
As with other Asian countries, shellfish allergies were the most common trigger of anaphylaxis in adults, they continued. Food anaphylaxis was the most common type in adults, which is in conflict with studies in Western populations that have instead named drug anaphylaxis as the most common type. [World Allergy Organ J 2015;8:32]
“In Singapore, the predominance of food anaphylaxis in adulthood might be related to the nature of shellfish allergy and its persistence into adult life. Additionally, we postulated that house dust mite (HDM) sensitisation due to the pan-allergen tropomyosin was the underlying reason behind the described cases” of anaphylaxis to shellfish, said researchers. [Allergy Asthma Immunol Res 2016;8:101-106]
In the present study, researchers enrolled patients from three emergency departments across Singapore: National University Hospital, KK Women’s and Children’s Hospital, and Tan Tock Seng Hospital. Only cases of anaphylaxis that satisfied the criteria set by the World Allergy Organisation were eligible for inclusion.