Acute or chronic injuries without freezing of tissue may result from cold exposure.
Frostnip
The mildest cold injury is frostnip. Affected areas are numb, swollen, and red. Treatment is rewarming, which causes pain and itching. Rarely, mild hypersensitivity to cold persists for months to years, but there is no permanent damage to underlying tissues.
Immersion (trench) foot
Prolonged exposure to wet cold can cause immersion foot. Usually, injury is limited to peripheral nerves and the vasculature, although muscle and skin tissue may be injured in severe cases.
Initially, the foot is pale, edematous, clammy, cold, and numb. Tissue maceration may occur if patients walk extensively. Rewarming causes hyperemia, pain, and often hypersensitivity to light touch, which can persist for 6 to 10 weeks. Skin may ulcerate, or a black eschar may develop. Autonomic dysfunction is common, with increased or decreased sweating, vasomotor changes, and local hypersensitivity to temperature change. Muscle atrophy and dysesthesia or anesthesia may occur and become chronic.
Immersion foot can be prevented by not wearing tight-fitting boots, keeping feet and boots dry, and changing socks frequently (1).
Immediate treatment is rewarming by immersing the affected area in warm (37 to 39° C) water, followed by sterile dressings. Nicotine should be avoided (2). Chronic neuropathic symptoms are difficult to treat; if amitriptyline fails, gabapentin may be tried (see Neuropathic Pain: Treatment).
Chilblains (pernio)
Localized areas of erythema, swelling, pain, and pruritus result from repeated exposure to damp nonfreezing cold; the mechanism is unclear. Blistering or ulceration may occur. Chilblains most commonly affects the fingers and pretibial area and is self-limited. Occasionally, symptoms recur. Younger women are most commonly affected, including some who may have Raynaud phenomenon or underlying autoimmune disorders (eg, systemic or cutaneous lupus erythematosus) (3).
The middle phalanx has areas of localized erythema and appears swollen.
© Springer Science+Business Media
Swelling and blistering on the pads of the toes result from repeated cold exposure without freezing.
Image courtesy of Karen McKoy, MD.
This image shows the swelling and erythema of chilblains.
Image courtesy of Karen McKoy, MD.
The middle phalanx has areas of localized erythema and appears swollen.
© Springer Science+Business Media
Swelling and blistering on the pads of the toes result from repeated cold exposure without freezing.
Image courtesy of Karen McKoy, MD.
This image shows the swelling and erythema of chilblains.
Image courtesy of Karen McKoy, MD.
Endothelial and neuronal damage results in vasospasm and exaggerated sympathetic response when exposed to cold. First-line treatment typically involves conservative measures, such as keeping the affected area warm and dry and avoiding nicotine. Data to support the use of pharmacologic agents are limited. Nifedipine and topical corticosteroids are the most commonly used and may help reduce symptoms. Other approaches, such as pentoxifylline or tadalafil, may also be of benefit (3).
References
1. Mistry K, Ondhia C, Levell NJ. A review of trench foot: a disease of the past in the present. Clin Exp Dermatol. 2020 Jan;45(1):10-14. doi: 10.1111/ced.14031
2. Zafren K, Hollis S, Weiss EA, et al. Prevention and Treatment of Nonfreezing Cold Injuries and Warm Water Immersion Tissue Injuries: Supplement to Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite. Wilderness and Environmental Medicine. 34(2):172-81, 2023. doi.org/10.1016/j.wem.2023.02.006
3. Dubey S, Joshi N, Stevenson O, Gordon C, Reynolds JA. Chilblains in immune-mediated inflammatory diseases: a review. Rheumatology (Oxford). 2022 Nov 28;61(12):4631-4642
