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Outdoor First Aid

The 10 Most Common Hiking Injuries and Illnesses and How to Treat Them

Learn how to treat the most common wilderness maladies with our guide to dealing with everything from bellyaches to broken bones.

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Wilderness maladies strains and sprains

Treating sprains. Illustration by Peter Sucheski

In the backcountry, anything can go wrong at any time. Unfortunately, “anything” is hard to prepare for. We dug into the numbers from the National Outdoor Leadership School (NOLS) database of medical incidents to figure out what you really need to worry about out there. Here’s how to save your trip—and maybe even your life

Want to learn more? Sign up for our online Wilderness First Aid Basics class.

Strains & Sprains

Strains affect muscles while sprains involve ligaments and tendons (for hikers, that usually means ankles and knees). Either way, expect pain, swelling, or restricted range of motion, often after a snap or pop. Because they require rest to heal, these injuries can be trip-enders.

Pack Ibuprofen or acetaminophen

Prevent Strengthen joints, stay fit, and warm up and stretch before hiking. Wear sturdy boots if you’re prone to rolled ankles, use trekking poles, and step carefully.

Treat Your goal is to reduce swelling.

1. Soak the injury in a cold river or lake, ice it with packed snow wrapped in clothing, or apply a cool, damp cloth as needed for short-term pain control.

2. Wrap in an elastic bandage (loosen if circulation is impaired). Massage and gently stretch muscular injuries.

3. Elevate the limb above the heart during rest (about 20 minutes for a mild case; all night for a serious one).

Evacuate if the affected limb is unusable.

Abdominal Pain

The trouble with a bellyache is that it can be a symptom of anything from gas to a GI infection to kidney stones, which makes it hard to diagnose in the field. Some of these are serious, some—not so much.

Pack Antacid, Pepto-Bismol, thermometer to check for fever

Treat Alleviate symptoms by assuming the fetal position to relax abdominal muscles until you can get help to address the underlying issue. Drink plenty of fluids and eat bland foods.

Evacuate if pain:

  • Is localized (more than just a general crampy feeling) and persists for more than 12 hours.
  • Coincides with blood in the urine, feces, or vomit or a fever of 102°F or higher (which can indicate anything from shock to appendicitis).
  • Might be related to pregnancy or internal injury.
  • Intensifies with movement, and/or the abdomen feels rigid or painful to the touch.
  • Doesn’t go away within 24 hours.
Wilderness maladies allergic reactions
Poison plants. Illustration by Peter Sucheski

Allergic Reactions

Most reported reactions are due to either preexisting allergies like hay fever or run-ins with poisonous plants. (Bee stings aren’t included in this category.)

Pack Tecnu, a skin cleanser, to wash off oils; topical cortisone or antihistimine for itching

Prevent Learn to ID the area’s dangerous vegetation, like poison ivy. Wear long pants and sleeves when walking through underbrush, and avoid touching those clothes (wash them post-trip; experts aren’t sure how long oils remain active).

Treat Wash up ASAP. Urushiol—the oil found in poison ivy, oak, and sumac—takes 10 minutes to bond to skin. Avoid scratching, which can cause infection or spread oils.

Evacuate if the rash/blisters get infected (look for severe oozing, swelling, heat, and spreading red lines).

Nausea, Vomiting, & Diarrhea

It’s easy to blame Giardia for this unholy trinity, but your hand-washing habits (and those of your campmates) are the more likely culprit.

Pack Pepto-Bismol, acetaminophen, Imodium (for short-term stoppage), thermometer

Prevent Wash dishes with soap and hot water. Wash hands with soap and scrub for at least 20 seconds, attacking all surfaces—including under fingernails. Generously globbing hand sanitizer on dirt-free skin works, too.

Treat Rest and hydrate (drink when you’re thirsty; don’t skimp on the electrolytes), and wait it out (usually 24 to 48 hours).

Evacuate if cramping pain lasts 24 hours, you can’t keep liquids down, or your fever tops 102°F.

Toothaches & Chipped Chompers

Bacterial dental infections happen, but overambitious chewing and face-first falls are the more common cause.

Pack Dental wax

Prevent Check food for windblown grit or sand before biting down (it happens more often than you’d think).

Treat Bite down on gauze to stop bleeding, then flush with treated water. Cover exposed nerves with a temporary filling (like Cavit), ski wax, or gum. Lost tooth? If you’re close to the trailhead, gently clean it, stick it back in its socket, and hurry—you only have about an hour to save it.

Evacuate to save a lost tooth or if you spot symptoms of infection (red or swollen gums).

Frostnip & Frostbite

Look for white, waxy skin and a tingling feeling (signs of frostnip). Skin that feels hard and numb and dents with pressure, or is frozen solid, indicates frostbite (especially on the fingers, toes, and face).

Pack Ibuprofen, gauze bandages

Prevent Keep warm and dry, and avoid restrictive clothing or boots.

Treat Immediately rewarm mild cases with skin-to-skin contact in your (or a partner’s) armpit or groin. Deeper frostbite? Immerse in water just above body temperature until all numbness fades, then bandage. Don’t rub frozen tissue or use radiant heat (like from a fire or camp stove) for thawing—it’s easy to burn yourself when you can’t feel your skin.

Evacuate all but the mildest cases.

Flesh Wounds

Most reported soft tissue injuries involve cuts, scrapes, burns, or blisters, but blisters are by far the most common.

Wilderness maladies blisters
How to treat a blisterIllustration by Peter Sucheski


Pack Bandages, duct tape, moleskin, antibiotic ointment

Prevent Break in footwear, keep feet dry (change socks after accidental submersions or big sweats if necessary), and address hot spots immediately.

Treat Apply duct tape, medical tape, or Moleskin to hot spots. Too late?

1. Clean bubble-ups with soap and water.

2. If you think it’ll burst in your boot, pop with a flame-sterilized needle or knife.

3. Apply antibiotic ointment. Bandage with a donut-shaped piece of moleskin.

4. Cover in tape.

Cuts and Scrapes

Pack Bandages, gauze, antibiotic ointment

Prevent Cut away from yourself when prepping food or firewood, and store sharp objects in your pack with care.

Treat Flush grit from the wound with about a liter of water (nip the corner off a plastic bag, fill with water, and squeeze to create a jet). Got a bleeder? After cleaning, hold gauze over the wound and apply firm pressure. If the gauze soaks through, add more. When bleeding stops, bandage to hold the gauze in place.


Pack Bandages, gauze, antibiotic ointment

Prevent Cook on a flat surface, and arrange all ingredients and utensils in a semicircle within arm’s reach to prevent accidental knock-overs

Treat Run cold water over the burn for 10 minutes to cool, then clean, apply antibiotic ointment, and wrap with gauze.

Evacuate if you get a severe infection—you’ll see little red lines trailing away from the injured area, a sign of inflamed blood vessels. Plus, it’ll be painful to the touch.

Flu-like Illness

Pack Ibuprofen or acetaminophen, cough drops, thermometer

Prevent Wash hands frequently. Cover your mouth when coughing, and don’t let anyone reach into your gorp bag.

Treat It’s the same in the backcountry as it is at home: Rest as much as you can and stay hydrated.

Evacuate if you have a fever above 102°F for more than 48 hours, headache with a stiff neck, or a throat so sore it’s hard to swallow.

Genito-urinary Issues

If it burns when you pee, you probably have a UTI. Nasty itching in the lady parts? It might be a yeast or bacterial vaginal infection.

Pack Pyridium for UTIs, Monistat or another antifungal if you know you’re prone to yeast infections

Prevent Keep clean (read: wet wipes), especially when romantic activities are involved. Wear quick-dry undies to prevent sweat buildup.

Treat Staying well-hydrated can be enough to flush a UTI, but over-the-counter drugs speed things up. Positive you’ve got a yeast infection? Use an over-the-counter antifungal medicine. Not sure? See a doctor.

Evacuate if a UTI worsens, as the infection could spread. Also hike out if you have any testicular swelling or pain; that can indicate a condition that requires serious medical attention.

Broken & Dislocated Bones

Fractures are most common in the leg, ankle, or wrist after a fall (symptoms are similar to those of sprains and strains, but more severe). For dislocations, which usually affect the shoulder, you’ll feel pain and restricted range of motion (most common cause: pushing past a planted ski or trekking pole or levering your arm while paddling).

Pack SAM splint; elastic bandage.

Prevent Use trekking poles and exercise caution when scrambling. Leave your hands out of the wrist straps on poles.

Treat Immobilize the injury (don’t try to pop a dislocation back in place). For a leg injury, follow these steps:

1. Place a foam or uninflated sleeping pad under the leg. Pad the area under the leg with clothing; place a rolled-up item of clothing under the knee to keep it from locking out.

2. Tie the pad around the leg with at least two strips of cloth—one above and one below the knee.

3. Tie the pad’s extra length around the foot like a boot (the wrap should support the ankle and keep it at as close to a right angle as possible to limit movement). Inflate the pad, if using a blow-up. Loosen if circulation is impaired.

Evacuate any break or dislocation. If the victim can walk out, great. But call for help if you see bone break through skin or a limb at an odd angle, or if there’s no sensation or pulse below the injury.

Take a Class

All backpackers should have a solid foundation in wilderness first aid. Here are some options for online and in-person instruction:

BACKPACKER’s Wilderness First Aid Basics

This self-paced online class covers assessing sick and injured people, making emergency response plans, and treating a variety of medical issues. $149

NOLS Wilderness First Aid

Get hands-on practice in mock emergency exercises—and WFA certification—with these two- or three-day classes held across the country. $160-$400

What makes people sick in the backcountry?

Just how common is acute mountain sickness? Are you more likely to be felled by heat or cold? While rates of AMS obviously increase on high altitude peaks, and dehydration risk is higher in places like the Grand Canyon, here’s how the major illnesses stack up in the NOLS database.

6% Mental health issues

5% Dehydration

2.9% Acute mountain sickness

1% Appendicitis

1% Asthma

0.7% Cardiac issues

0.6% Hypothermia

0.5% Heat illness

0.5% Diabetes issues

0.4% Seizure

0.3% Tick-related illness

0.2% Anaphylaxis

*The data is compromised of all reported incidents (about 2,000 total, divided into illness and injuries) on NOLS trips between 2005 and 2010. Percentages refer to the percents of total reported injuries or total reported illnesses during this timeframe.

Meet the Experts

Tod Schimpelfenig, Curriculum Director, NOLS Wilderness Medicine

Dr. Jeffrey L. Pellegrino, Member, American Red Cross Scientific Advisory Council

Stephen Leavins, Lead Instructor, Wilderness Medical Associates

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