Technetium-99 or MR scans are not required for diagnosis, but might be useful for prognostic purposes. Prevention
The Wilderness Medical Society recommends covering the skin and scalp, taking in adequate nutrition, avoiding constrictive footwear and clothing, and remaining active without causing exhaustion. Supplemental oxygen might also be of use at high elevations. Repeated exposure to cold water makes people more susceptible to frostbite. Additional measures to prevent frostbite include:
Avoiding temperatures below −23 °C (-9 °F)
Avoiding moisture, including in the form of sweat and/or skin emollients
Avoiding alcohol and drugs that impair circulation or natural protective responses
Layering clothing
Using chemical or electric warming devices
Recognizing early signs of frostnip and frostbite

Treatment
Individuals with frostbite or potential frostbite should go to a protected environment and get warm fluids. If there is no risk of re-freezing, the extremity can be exposed and warmed in the groin or underarm of a companion. If the area is allowed to refreeze, there can be worse tissue damage. If the area cannot be reliably kept warm, the person should be brought to a medical facility without rewarming the area. Rubbing the affected area can also increase tissue damage. Aspirin and ibuprofen can be given in the field to prevent clotting and inflammation. Ibuprofen is often preferred to aspirin because aspirin may block a subset of prostaglandins that are important in injury repair.The first priority in people with frostbite should be to assess for hypothermia and other life-threatening complications of cold exposure. Before treating frostbite, the core temperature should be raised above 35 °C.
Pathophysiology
The pathological mechanism by which frostbite causes body tissue injury can be characterized by four stages: Prefreeze, freeze-thaw, vascular stasis, and the late ischemic stage. Prefreeze phase: involves the cooling of tissues without ice crystal formation. Freeze-thaw phase: ice-crystals form, resulting in cellular damage and death. Vascular stasis phase: marked by blood coagulation or the leaking of blood out of the vessels. Late ischemic phase: characterized by inflammatory events, ischemia and tissue death. Diagnosis
Frostbite is diagnosed based on signs and symptoms as described above, and by patient history. Other conditions that can have a similar appearance or occur at the same time include:

Frostnip is similar to frostbite, but without ice crystal formation in the skin. Whitening of the skin and numbness reverse quickly after rewarming. Trench foot is damage to nerves and blood vessels that results exposure to wet, cold (non-freezing) conditions. This is reversible if treated early. Pernio or chilblains are inflammation of the skin from exposure to wet, cold (non-freezing) conditions. They can appear as various types of ulcers and blisters. Bullous pemphigoid is a condition that causes itchy blisters over the body that can mimic frostbite. It does not require exposure to cold to develop. Levamisole toxicity is a vasculitis that can appear similar to frostbite. It is caused by contamination of cocaine by levamisole. Skin lesions can look similar those of frostbite, but do not require cold exposure to occur.People who have hypothermia often have frostbite as well. Since hypothermia is life-threatening this should be treated first.