High altitude activities lead to different exposures to the skin, which include low humidity, high-velocity wind, excessive ultraviolet (UV) light exposure, and extreme cold temperatures. In the review article from Samantha Schneider, published in Dermatology Journal (Schneider, 2017), dermatologic injuries are examined. We prepared a short version of this interesting scientific publication for you.
There are several skin pathologies related to cold exposure.
Frostbite occurs when the temperature in the skin and deeper tissues reaches sub-freezing (0°C) temperatures, causing cellular injury and death. Important environmental risk factors for the development of frostbite include high humidity, low temperatures, wind chill, high altitude, and prolonged exposure to the elements. Other risk factors include wearing tight constrictive clothing, immobility, nicotine use, medical diseases vascular disease, diabetes mellitus, or vasoconstrictive disorders such as Raynaud disease, and use of vasoconstrictor medications (such as clonidine). Women also tend to be more commonly affected than men. The risk of injury related to frostbite is closely related to one’s preparedness, any preexisting medical conditions, the body’s physiologic response to the environment, and any previous cold injury. When preparing to spend time out in the elements at altitude, one should ensure good hydration and nutrition, dress in non-restrictive layers to cover all skin and scalp, optimize prior medical conditions, avoid wet extremities, and use chemical warmers. In severe cases, when the patients experience significant tissue loss, a surgical intervention including amputation is required. Treatment consists primarily of rapid re-warming via a water bath of 40-42°C. However, rapid re-warming should only be attempted if the tissue is not at risk of refreezing. Upon initial re-warming, patients may have significant numbness followed by a burning, aching sharp pain.
Frostnip is a non-freezing injury that is associated with severe vasoconstriction. It is commonly thought to be a precursor to frostbite as it occurs in a similar distribution (cheeks, ear, nose). Icicles form on the skin’s surface giving the appearance of frost. However, there are no icicles within the skin and thus no long-term consequences of frostnip. Patients present with numbness and pallor on exposed skin that resolves quickly following rewarming.
Trench Foot is another non-freezing cold injury. Trench foot occurs when the feet are exposed to cold (temperatures >0°C) and wet environments for prolonged periods of time. Initially, with stage one, patients develop erythema, edema, and tenderness. Over the next day or two, patients develop stage two, which consists of paresthesias and numbness with marked edema and occasional bullae. Lastly, patients can progress to stage three, which consists of gangrene. It is recommended that those at risk for or with a history of trench foot change their shoes and socks frequently in cold, wet conditions. Additionally, one may try prophylactic treatment with anti-perspirants that include aluminum hydroxide to decrease perspiration on the feet.
Cold urticaria is a type of physical urticaria that results from exposure to cold environments. It is thought to be a type of allergic response to cold that results in erythematous pruritic hives with or without angioedema within minutes of exposure to cold environments. Aside from the skin manifestations, patients can also have systemic symptoms including fatigue, headache, dyspnea, and tachycardia. Cold urticaria affects men and women equally with most patients presenting in young adulthood (second or third decade of life). Patients with cold urticaria can be prophylactically treated with antihistamine medications.
Solar exposures can also lead to several dermatologic manifestations.
Skin cancer is one the most common form of cancer. A study of 283 male mountain guides in Germany, Switzerland, and Austria found that mountain guides were at greater risk of developing both pre-malignant lesions as well as skin cancer, demonstrating an association between high occupational UVR exposure and increased prevalence of both precancerous skin lesions and skin cancer. In all types of skin cancer, the most modifiable risk factor is UVR from sun exposure. Certain environmental factors can increase the amount of UVR including simply being at higher altitudes, as well as clear skies, and reflective surfaces including snow, sand, and water.
Seborrheic dermatitis is a mild chronic inflammatory skin condition that affects areas of the skin with large sebum production including the scalp, ears, face, central chest, and intertriginous areas. It is described as sharply demarcated pink-yellow to red-brown patches with flaky, greasy scales in a seborrheic distribution. A study performed in Austria, Switzerland, and Germany in the late 1990s, found that 16.3% of mountain guides had evidence of dermatologist diagnosed seborrheic dermatitis.
Severe Weather Exposures
Lightning strikes remain the second most common cause of deaths related to storms and inclement.
Lightning strikes affect as many as 400 people annually in the United States resulting in approximately 40 deaths. Lightning can be both positively or negatively charged as well as have direct or alternating current. A single bolt of lightning contains as much as 30,000-110,000A. However, the energy is only applied for a few milliseconds creating little opportunity for transfer to the body. There are several different types of lightning strikes: direct strike, contact injury (when lightning strikes an adjacent object that is touching the patient), side splash (when the current jumps from a nearby object to the patient), and ground current (when the lightning travels through the ground to strike the patient). Ground current is the most common mechanism of a lightning strike.
Prevention is key when it comes to lightning exposure. Signs of an imminent lightning strike include a blue haze around objects (known as St. Elmo’s fire), static electricity over skin or hair, ozone smell, or a nearby crackling sound. In the wilderness, one should avoid being in high-risk areas such as ridgelines and summits, as well as avoid tall isolated objects (i.e. trees). Additionally, one can attempt to insulate oneself from the ground by sitting on a pack (after removing any metal), a dry coiled rope, or a rolled foam sleeping pad. Groups should spread out to avoid mass casualties.
In patients struck by lightning, the amperage the patient receives determines the severity of their injuries. A low amperage injury may lead to paresthesias whereas a high amperage injury can cause ventricular fibrillation and respiratory or cardiac arrest. After a lightning strike, an initial evaluation of the patient’s cardiac and respiratory status is paramount, followed by initiation of cardiopulmonary resuscitation while awaiting emergency medical services. A pathognomonic skin finding found in lightning strike victims is the Lichtenberg figure (a unique red colored fern-like pattern). It typically appears within an hour of the lightning strike and resolves within 24-48 hours. After a lightning strike, patients may also experience burns including linear burns, punctate burns, and full-thickness burns. Linear burns form as a patient’s sweat is vaporized during the electrical current causing a partial-thickness burn (also known as a flashover).
There are many possible exposures in the wilderness that can result in dermatologic manifestations. If one knows the emergent warning signs and practices good prevention, exploring the great outdoors can be thrilling and safe.