Wilderness Medical Series — Module 13

Treating Burns and Blisters in the Field

How to assess, treat, and dress burns and blisters in a wilderness setting — from TBSA calculation to mole foam donuts and improvised options.

By Joshua Enyart · Founder & Head Instructor, Gray Bearded Green Beret

Former Army Ranger, Green Beret, and full-time survival instructor · three decades of professional instructor experience

Burns and blisters are the most common injuries in the wilderness that most people underestimate until they have one. Neither looks dramatic in the early stages. Both escalate fast when mismanaged, and both carry a real infection risk that compounds over the duration of a multi-day trip.

This article covers the full spectrum: how to assess burn severity, how to select the right dressing, and how to manage blisters from the first hot spot through an open wound. These techniques are calibrated for the reality that you may be treating these injuries hours or days from definitive medical care.

Burn Classification: What the Degrees Tell You

Burns are classified by depth of tissue involvement. First degree burns are superficial — similar to sunburn. No blistering, skin integrity is largely intact. Critically, first degree burns do not count toward your total body surface area calculation when making treatment decisions.

Second degree burns compromise the top skin layer and typically produce blistering. These count toward TBSA. Third degree burns penetrate past the skin into deeper tissue. Fourth degree burns reach muscle and bone — rare in typical wilderness settings but representing the severe end of the thermal injury spectrum.

For practical field medicine, the specific degree matters less than total body surface area affected. Your dressing decision is driven by TBSA, not degree.

Calculating Total Body Surface Area

TBSA is your primary decision metric. Two field methods exist.

The Rule of Nines

The Rule of Nines divides the body into segments each representing approximately 9 percent of total surface area: head and neck (9%), each arm (9%, both = 18%), each thigh (9%, both = 18%), each lower leg (9%, both = 18%), anterior torso (18%), posterior torso (18%), perineum (1%). Apply this to estimate what percentage of the body has second degree or worse burns. First degree burns are excluded from the calculation.

The Palm Method

The patient's own palm equals approximately 1 percent of their total body surface area. Count palm-widths across the burned area to estimate TBSA for smaller or irregular burns.

Burn Treatment Protocol: Four Steps in Sequence

Step 1: Remove the Source

Before any treatment, remove the patient from the heat source or the source from the patient. Continued exposure worsens the burn with every second. Nothing else happens until the source is eliminated.

Step 2: Cool the Burn

Apply cold water to the burned area to interrupt continued tissue damage from retained heat. A hydrogel burn dressing simultaneously cools and covers the wound. For large burns, limit extended cold water application — cooling a large surface area accelerates heat loss and can contribute to hypothermia.

Step 3: Clean the Wound

Burns are highly susceptible to infection because the skin barrier has been compromised. Before applying any dressing, clean the burn with the cleanest available water. This step will be painful but is not optional. Infection in a burn wound progresses rapidly in a backcountry environment where dressing changes are limited.

Step 4: Cover with the Appropriate Dressing

Dressing selection is determined by TBSA. Burns at 10 percent TBSA or less receive a wet dressing — the moisture provides cooling and is significantly more comfortable against exposed nerve endings. Burns greater than 10 percent TBSA receive a dry dressing. A large burn destroys the skin's ability to regulate core temperature; a wet dressing over a large burn area accelerates heat loss and puts the patient at hypothermia risk on top of the burn.

Wet dressing for 10% TBSA or less. Dry dressing for greater than 10% TBSA.

Change all burn dressings at least every 24 hours. Burns are an evacuation emergency regardless of size — infection risk is high within the first 72 hours. A burn sustained early on a multi-day trip should prompt a serious reassessment of whether the trip continues.

Improvised Wet Dressing

When no commercial burn dressings are available and the burn is 10 percent TBSA or less: apply water to clean gauze, place the wet gauze directly over the burn, and secure with a dry outer cover dressing. The wet inner layer replicates the cooling function of a commercial hydrogel dressing. The dry outer layer keeps the environment out. Hydrogel burn dressings also work well on open blisters — a blister is a friction burn, and the same barrier and cooling logic applies.

Blisters: Prevention Is the Whole Game

A blister is a friction burn — heat from repetitive friction concentrated at one point on the foot. In a backcountry setting, a serious blister can compromise a person's ability to walk out. That makes blister management a tactical problem, not just a comfort issue.

During extended military operations on foot with heavy loads, blisters were constant. The lesson from that environment applies directly to the wilderness: the moment you cut a corner on footwear, sock quality, or foot care, you pay for it in the days that follow. Wear well broken-in boots. Quality socks reduce friction and wick moisture. Keep feet clean and change socks when saturated. Carrying three pairs — one on the foot, one drying on the outside of the pack, one clean and ready — is a simple system that pays real dividends on extended trips.

Hot Spots: Stop and Fix It Now

A hot spot is a localized sensation of heat or friction at one point on the foot — the precursor to a blister. The moment you feel it, stop. Remove the boot. A hot spot treated in two minutes costs almost nothing. A hot spot ignored for two more miles becomes a blister that costs you the next three days.

Apply moleskin — thin adhesive sheet — directly over the hot spot to reduce friction. Gorilla tape, duct tape, or 100-mph tape works as an improvised substitute. Round all corners of any material before applying. Square corners catch on the sock interior, begin peeling up, and create a rolled edge that generates more friction than the original hot spot.

Three Thicknesses of Commercial Blister Material

Three commercial options exist, used progressively as blister severity increases. Moleskin — paper-thin — is best for hot spots and light friction protection. Moleskin with padding adds a thin foam layer for situations requiring more cushioning. Mole foam is the thickest option, providing significant standoff between boot interior and blister surface when a developed blister needs protection. As a blister progresses, progressively thicker material is used to keep the boot from pressing directly on the wound.

Managing a Closed Blister

A closed blister has the overlying skin intact, containing a pocket of fluid the body produced intentionally — cooling the injured tissue and protecting the new skin forming beneath. Preserve that closed state as long as possible. Leave a closed blister intact unless it is large enough to prevent walking.

The mole foam donut is the standard technique: cut a piece of mole foam with a hole in the center sized so the blister sits inside it. The foam surrounds the blister on all sides, eliminating direct boot pressure on the blister surface. Place the mole foam donut over the blister, then cover the entire assembly with a layer of thinner moleskin to seal and protect the surface. This two-layer approach maintains the intact blister skin as a protective barrier.

Draining When Necessary

If the blister prevents walking, drain it in a controlled manner rather than allowing it to rupture on its own. Use a safety pin or sail needle. Insert at the base of the blister on the downward-facing surface — for a heel blister, at the bottom toward the ground. Create a small hole and gently press out the fluid. Preserve the overlying skin — it remains protective even after drainage. Apply the mole foam donut immediately, and expect the blister to begin refilling at rest stops.

Managing an Open Blister

An open blister has the overlying skin torn away, exposing raw new tissue. This is the most painful state and carries the highest infection risk.

Trim any dead or hardened skin at the wound edges — dead dry skin creates additional friction against the raw surface. Pad around the open wound with the standoff donut approach to create space between boot and wound. Cover the raw surface to protect it from the environment. Tincture of benzoin applied to the skin around the dressing edges — not to the wound itself — improves adhesion of the padding. Caution: benzoin on an open wound surface burns for approximately 10 to 20 seconds before subsiding.

Improvised Blister Management

When commercial moleskin and mole foam are unavailable, gorilla tape, duct tape, or 100-mph tape addresses all three blister states. For standoff, build a tape donut: roll tape back on itself multiple times to build thickness, cut a hole in the center sized to accommodate the blister, round all outer corners, and place the assembly over the blister. Cover with tape. For closed blisters where boot space is too tight for any padding, a piece of plastic cut from a Ziploc bag secured with tape creates a low-profile friction barrier without adding significant volume inside the footwear.

Infection Watch Over Extended Trips

Change blister dressings at least once daily using the cleanest available material. Watch for infection signs at every dressing change: increasing redness extending beyond the wound edges, increasing warmth, pus, fever, or red streaking. Infection in a blister or burn wound in the field accelerates the evacuation decision. Clean technique at every dressing change is the primary preventive measure when sterile conditions are not achievable in the backcountry.

About the Author: Joshua Enyart is a former Army Ranger and Green Beret, and full-time survival instructor with three decades of professional teaching experience in wilderness medicine, survival, and field craft.

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