Suppose you are out hiking, many hours from the trail head and someone has a severe allergic reaction (ie, anaphylactic shock or Anaphylaxis). In this case, what is the best course of treatment to maximize their chance of survival until they can reach a hospital?
Anybody who has severe allergies which could lead to anaphylaxic shock should carry appropriate medication with them. Typically, that would consist of:
- An antihistamine (e.g. benadryll)
- An epinephrine auto-injector (aka "Epi-Pen")
Benadryll is available over the counter and you should have it in your first aid kit. Epi is by prescription only (at least in the US), so the individual who has allergies should carry their own. If you're leading a large group, you may be able to get a prescription and standing orders for trained staff to carry and administer epinephrine to group members.
Many people think that just injecting epi when somebody has an anaphylactic attack is the entire treatment. It's important to know that epinephrine does not fix the underlying issue! It only helps to reduce swelling, helping to re-open the airway. You must fix the cause of the reaction!
As soon as an exposure to a known allergen occures – even if the person isn't having a visible reaction – you need to immediately have the person take an antihistamine. Antihistamines are drugs that suppress the histamine response, i.e. the body's overreaction to an antigen. This is what actually reduces the severity of the allergic reaction itself. Correct dosage depends on the person; consult the instructions on the antihistamines or talk to a doctor.
The important consideration with an allergic reaction is maintaining a clear airway. If you get the antihistamines into the patient immediately, it's possible that the reaction will be contained and the patient will not develop anaphylaxis. In the event that they do develop anaphylaxis, that's where you need to monitor their airway and administer epi if necessary. If the patient is having difficulty breathing, encourage them to take deep, calm breaths, and to pace their breathing off yours.
If the patient is unable to maintain a clear airway, be prepared to administer epinephrine. Epi-pen trainer kits are widely available through first aid training programs, so if you expect to be traveling in the wilderness with people who may require epi, you should do the training. The auto-injectors have clear instructions on them; typically you just remove the blue cap, place the orange end of the auto-injector on their thigh, push down hard on the epi-pen to trigger the injector, and hold it in place for at least 30 seconds. The epi is administered automatically at the correct dosage. Make sure to carefully follow the directions as individual auto-injectors may vary in how exactly they are administered. Epi wears off after 10-15 minutes, so most people will carry either a dual-injector or two injectors, so that a second dose can be administered if necessary. When injecting, always hold the injector gripped in your fist, do not place anything over either end of the pen to ensure you don't accidentally inject it into yourself!
Make sure to monitor the patient's vital signs throughout, and continue to monitor their condition after the initial treatment. Ensure that any secondary issues such as bleeding from a bite, etc. are taken care of as well.
Once you've stabilized the patient, you need to start planning for an evacuation. Anaphylactic reactions are life threatening. If you are in a very remote area and have access to an emergency locator beacon or other outside communication, it's appropriate to request emergency assistance.
As always, the most important thing is to be adequately prepared. Understanding the allergies (and other medical concerns) your group members have, what treatment options they have, and how to use them is critical. You should know all of this information for every member of your party before heading into the wilderness, so that if an emergency situation does arise you're already prepared. Most people with medical concerns which could require your immediate intervention will be happy to show you how to handle it should they need your help. In this particular example, epi injectors differ in appearance and operation, and knowing exactly how to use the injectors belonging to members of your party will save you precious time should you actually need to use them.
Note: This information is based on my training as a wilderness first responder and the accompanying textbooks and practice. Reading medical advice on the internet is no substitute for proper medical training. This information is provided as-is, with no guarantee of correctness or effectiveness. You alone are responsible for ensuring an appropriate level of training for the activities you engage in, including administering first aid to yourself and others. Neither Stack Exchange, the author, nor any other party shall be responsible for any harm that comes to you or others by following any advice in this post.
An epi-pen buys you 15 to 30 minutes. You can follow up with benadryl for other antihistamine. But the patient needs to understand what to do. For a back country activity the patient needs sufficient antihistamine to get over the incident or back to medical facility.
This is a serious incident. I have worked with people who were seriously allergic to bee stings. When they got stung, it was, "epi-pen NOW. Drive me to a hospital. Watch me for relapse, here's the second epi-pen if I stop breathing"
One other person I knew was so allergic she had a pen in each car, bathroom, and in her purse. That way she had 2 to get her to the hospital.
In the backcountry the extreme problem is one where you have a previously unknown severe reaction. With bee/wasp stings it is common for someone to have mild to moderate reactions the first few times, that become more severe with later sting events. (Beekeepers wives are much more likely to be alergic than beekeepers or the general population. Beekeepers get stung enough that their body has a very mild reaction. Wives get stung consistently a few times a year, usually doing laundry.)
I have had a boy who disturbed a ground wasp nest and got 17 stings before he could get out of the area. He was not allergic. Someone who had a previous case that was at the 'chew 6 benadryl" level could be pushed into the "use an epipen" level.
That said: I've done 33 years of tripping an average of 5-6 weeks a year with groups of 20-40 people. I've yet to get above the 'take two benadryl" level. I've known two people who had severe alergies, one to bees, one to peanut oil. They knew their vulnerability and prepared accordingly.
Although an epi-pen-like device is the correct treatment for anaphylaxis, if the patient's airway is becoming obstructed, and adrenaline is not available (or has already been expended), several puffs (some sources say 8-10) from an asthma inhaler intended for treating an acute asthma attack, particularly one containing salbutamol (also known as albuterol), can provide some relief. Ideally, it should be delivered through a spacer.
In my experience, more people carry asthma inhalers than epi-pens. However, this should only be done when the patient's airway is swelling and potentially becoming obstructed (they will have a wheeze or difficulty moving air). In this case, the consequences of doing nothing may include the patient dying. Giving a drug to a patient who doesn't usually take it is not a good idea, as there's a risk of adverse reaction from the drug itself. Salbutamol also increases the heart rate. You should still seek emergency help.
Salbutamol is a bronchodilator, and will dilate the airways in the lungs, but will not help to relieve an upper airway obstruction.
This situation just happened to me in a remote Utah canyon while solo backpacking. It was very scary.
Not medical advice. I'm not an MD. These are my impressions from researching.
Carry a good supply of 50mg OTC Benadryl tablets on any hike if you have any reason to think you are anaphalaxis susceptible.
Carry an Epi-pen. Carry two or more on any protracted trip.
Consider using the Epi-pen if you have even a hint that your breathing is becoming restricted.
Be aware that if you are in a location where extraction is not immediate or perhaps even possible, the Epi-pen only might buy you a short amount of time.
Be sensitive to known allergen conditions at a given time of year.
Understand that episodes will likely be recurrent.
Get medical attention ASAP. Reality is that if you are in a wilderness situation, this is likely not going to happen.
Maybe get a SPOT emergency device, though I'm not sure how effective it would be in these deep narrow canyons.
Consider the cost of wilderness emergency extraction. I imagine the cost would be huge and I have no idea how I would pay for such an event.
There comes a point in life when solo hiking may not be the best idea.
Know when to call it a day.
About a two months before I had developed an episode of Angioedema, facial, tongue, and throat swelling, presumably an allergic reaction from a medication I was taking. This ended in the ER with intravenous Benadryl and Steroids resolving the episode.
At age 55 I have never before had an allergic reaction.
I stopped taking the suspected medication and the problem seemed to resolve. I was given a prescription for an Epi-pen, which I filled.
Last week I took my yearly spring backpacking trip to southern Utah. A four day trip was planned in canyon country. Sometimes I go on these trips accompanied and sometimes alone. I have backpacked alone on and off for forty years and accept the risk.
The night before the trip I slept poorly and felt I was having some trouble breathing. A Benadryl resolved the breathing difficulty and I got some sleep.
The next day I started hiking thinking maybe I should call the trip off, but went ahead tentatively, with a plan to proceed or not depending on how I felt.
About six miles in I started feeling quite poorly. Breathing was labored, throat felt restricted and I increasingly felt like I was blacking out. I stopped, took off my pack and sat down to consider the situation. Despite stopping, I felt like my throat restriction was getting worse, and I think that my judgement was starting to become impaired. Perhaps there was a panic component, and I was hyperventilating. I don't really know.
I found my Benadryl and Epi Pen (which is not as easy as it sounds when alone in a mentally impaired condition), put them within reach, and took a Benadryl. Within 15 minutes I started to breath easier and feel better, and I felt like judgement was returning, and that maybe I could hike a bit.
Because I was feeling better I had the temptation to continue down the ever more remote canyon. After some consideration of what a wilderness extraction (or worse) would mean, I decided to return up canyon about a mile to a nice campsite and stay there until I felt better.
I had a very rough night, with a feeling of my throat closing any time I lay down, and used two 30mg Benadryl spaced about three hours apart.
I did not use the Epi-pen mainly because I had no idea how I might react to it. I should have done more research and should have used it.
The next day I felt somewhat better and was able to very slowly hike out the (what should have been easy) six miles to the trailhead and my car. It was very slow going.
I still have no idea what triggered this allergic event despite several subsequent visits to the allergist. I am suspecting Juniper or Cottonwood pollen which were in April heavy, but the allergist does not think these typically trigger Angioedema.