My friend, 20 weeks pregnant with her future adventurer, and I were sitting at the pool while a bee I fished out of the water was drying off and getting ready for flight again. “How do you know”, she asked me, “if your toddler is allergic to bee stings if he has not been stung before? A backpacking trip would not be a good time to find out.” And with that question, she cleanly had found the very shallow depth of my expertise.
Back at work the next day, I did a search of the medical literature. DISCLAIMER: I am not a physician. This is not a literature review. Scientific knowledge is found by trial and error. Please talk to your doctor if you have questions. Below is a summary of what I found, and some learning points I drew from it.
Existing Data on Allergic Reactions in Children
Allergic reactions are graded in literature from I (mild), II (moderate), III (severe) and IV (critical). If reactions are local they can range from mild (e.g. minor local swelling) to moderate (e.g. swelling of a limb). When reactions become systemic, they range from moderate (e.g. rash over the whole body) to severe (anaphylactic shock closing off airways). The prevalence in children for a systemic reaction is between 0.15 – 0.3 % (3 out of a 1000 children). 60% (3 out of 5) of those systemic reactions are mild to moderate, meaning it does not reach Grade III anaphylactic shock. Which means if a randomly selected 1000 children get stung by a bee, 1-2 of those would have a severe, systemic allergic reaction. Bees have about 2.5 times the venom load of wasps, making their stings higher risk. About 20 stings/kg body weight is considered lethal, although reports exists of individuals surviving considerably more stings.
Is there anything which could predict which children might be at risk? Several studies report that the risk of systemic reaction rises the more often a person is stung. An italian study
found a statistically significant correlation between insect bite allergies and allergies to dairy, eggs, and parietaria judaica (stickyweed pollen). There is a rare disease called mastocytosis
in which mast cells are more prevalent than typical, which leads to higher risk. Less than 200,000 people in the US are thought to have this disease.
Bern University Hospital (38,000 ER visits per year) did a 5 year review of all emergency patients with insect-related anaphylactic shock who visited the department 2009-2014. They found 143 patients, age ranged from 19-84 years. Incidence was highest on dry, war summer days. Only 16 patients needed epinephrine. Risk factors they identified was being male (60:40 ratio matching general ER visits), inattentive drinking/eating, and wearing open-toed shoes.
Unless my kid has any other allergies, the risk that the first insect sting will lead to anaphylactic shock is very small. Thinking back on myself growing up, playing in gardens, pools, and mountain meadow, I can recall getting stung a total of 4 times. First time was by a bee in my lower lip as it collided with me sitting on my grandmas bike cargo seat. The risk of getting my feet caught in the spokes or my fingers in the springs of her seat was considerably higher! No helmets in those days either. Second time was stepping on a bee on our lawn studded with daisies. Third time was absent-mindedly touching a flower on which a bumblebee sat. Third time was hooking my arm into a pool spill, where a bumblebee was sitting on the other side. That was the only time I got a moderate reaction with my lower arm swelling. Swimming 1000+ yards of freestyle after an insect sting to the body surface hitting the water is not exactly smart. Two of the stings I could have avoided, two were by chance. All happened within 10 minutes of a phone, although two of them in more rural areas of the country with a bit of a drive to the nearest emergency room.
Risk increases with exposure and age, which means avoiding stings is a good precaution. In order of priority for me:
1) Wearing closed-toed shoes while hiking is a good idea. Yes, I am a big fan of sandals and minimalist shoes. But considering evidence, closed-toe shoes might be a good idea when you are a ways from medical care with a child.
2) Teach your children to avoid stings by remaining calm. Bees and wasps only sting when provoked.
1) Limiting drinks to water will reduce the risk of stings due to inadvertently