Differentials
Cutaneous burns
INVESTIGATIONS
Clinical diagnosis.
Frostnip
SIGNS / SYMPTOMS
Frostnip is the mildest and most common form of freezing cold injury. Symptoms include pain and pallor, followed by numbness of exposed areas, such as cheeks, nose, ears, and digits. Rewarming the tissues results in return of sensation and function without further damage. The presence of frostnip is an indicator that environmental conditions are severe enough for frostbite, so precautions should be taken.[15]
INVESTIGATIONS
Clinical diagnosis.
Raynaud's phenomenon
INVESTIGATIONS
Clinical diagnosis.
Pernio (chilblains)
SIGNS / SYMPTOMS
Chilblains are a non-freezing cold injury, also known as pernio or perniosis. It is an inflammatory skin condition due to an abnormal vascular response to cold. Patients present with tender, pruritic red or blue lesions on the fingers, ears, toes, and nose. They have also been reported on the thighs and buttocks; however, they are less common in these locations. The lesions typically appear within 12 to 24 hours after cold exposure and resolve spontaneously in 1 to 3 weeks.
More than half of cases are idiopathic; however, studies have found an association of up to 20% to 40% with more concerning conditions, including systemic lupus erythematosus, cryoglobulinaemia, antiphospholipid syndrome, macroglobulinaemia, and chronic myelomonocytic leukaemia.[30]
Avoiding cold exposure is the best way to prevent chilblains. Treatment is best accomplished by drying and gently massaging the affected areas. The lesions are more painful upon rewarming. Active rewarming above 30°C (86°F) may significantly worsen the pain, so should be avoided.[1]
INVESTIGATIONS
Chilblains are a diagnosis of exclusion. Clinical evaluation involves full blood count, antiphospholipid antibody panel, cryoglobulins, cryofibrinogen, cold agglutinins, antinuclear antibodies, and serum protein electrophoresis. Chronic cases may require a biopsy to rule out other inflammatory processes. Histology shows papillary dermal oedema, perivascular lymphocytic infiltrates, and blood vessel wall oedema.
Immersion foot (trench foot)
SIGNS / SYMPTOMS
Trench foot, also known as cold immersion foot, is a non-freezing cold injury caused by prolonged exposure (between 12 hours and 4 days) to cold and wet conditions. Military personnel are particularly prone to this condition.
The suspected mechanism of action is alternating periods of vasoconstriction and vasodilation in the affected tissues. Prolonged exposure to near-freezing temperatures results in anaesthesia followed by hyperaemia, the latter of which can last for up to 3 months after the initial injury. The pain can recur with even slight re-exposure to cold, including commercial food lockers or freezers.
In contrast to frostbite, rapid rewarming in trench foot may lead to worsened hyperaemia and poor outcomes. Therefore, treatment involves slow rewarming.[15][31][Figure caption and citation for the preceding image starts]: Immersion foot (trench foot)Lloyd EL, BMJ 1994; 309:531-534 [Citation ends].
INVESTIGATIONS
Clinical diagnosis with a history of environmental exposure in wet conditions. The worst symptoms occur in the first few days. If symptoms continue to worsen, the diagnosis is unlikely to be a non-freezing cold injury (NFCI).
Use of this content is subject to our disclaimer