During the winter, there is a steady stream of people visiting the dermatology department for frostbite. However, some patients suffer not from real frostbite, but from other diseases similar to frostbite. If these patients are misdiagnosed, they may not be cured for a long time, or they may have serious consequences. Common diseases that are easily confused with frostbite are.
1. Cold erythema multiforme
It is the most common and easily confused skin disease with frostbite, mostly seen in children and adolescents. It usually appears as a purplish red or crimson papule at the onset of the disease, and can also have blisters, which can be accompanied by systemic symptoms. The cause of the disease is unclear, but it is generally believed to be a metabolic reaction of the small blood vessels in the human skin to physical factors such as cold. Due to the stimulation of cold and cause the human exposed parts of the small blood vessel contraction; long then the small blood vessel paralysis expansion to make the skin ischemia and hypoxia, while the venous return obstruction and cause bruising phenomenon, thus producing skin blood circulation disorders, so the appearance of erythema, blisters and even vesicles and other skin damage.
2.Familial “erythema”
It is a kind of autosomal dominant genetic disease, which is common in women, and often starts from infancy and lasts for a lifetime. It usually appears half an hour to four hours after exposure to cold, and the damage is an erythematous papule with a diameter of no more than 2 cm, not a real wind mass, without itching, but with a burning sensation; accompanied by fever, headache, arthralgia, myalgia, leukocytosis and other systemic manifestations. It can last up to 48 hours and is more likely to develop on exposure to cold air than cold water. If the immediate reaction with the ice test is negative, i.e., there is no windstorm. However, local erythema and deep swelling can occur 9 to 18 hours after the ice test.
3.Acquired “wind mass”
The cause of most patients is unclear, and some patients will disappear on their own after a few months or years of allergy to cold, but there are also those who do not heal. In addition, a few are caused by other diseases in the body. Within minutes of exposure to cold, itchy localized edema and wind eruptions appear, and in severe cases spread throughout the body. After entering a warm room for tens of minutes or hours, the wind masses can gradually subside and the itchiness is reduced.
4.Systemic lupus erythematosus
It is a relatively common autoimmune disease involving multiple systems, producing multiple autoantibodies due to cellular and humoral immune dysfunction. Its exact cause is unknown, and the pathogenesis is mainly due to the formation of immune complexes. The skin and mucous membranes are similar to frostbite. The skin and mucous membranes are similar to those of frostbite. For example, the patient’s face has butterfly-shaped erythema, edema, bright red color, slightly capillary dilation and scaly flaking in the acute stage, and blisters, ulcers, skin atrophy and pigmentation in severe cases; maculopapular rash and purple spots on exposed parts of the body skin.
5.Allergic vasculitis
Its pathogenesis is more complex, and it is generally believed that it is mainly caused by drugs and infections. The disease is mainly characterized by the occurrence of erythema nodosum in the lower extremities, with pressure pain, and may also be accompanied by purpura, purpuric papules, pemphigus, papules, necrotic ulcers and other polymorphic damage as the main manifestation.
6.Erythema nodosum
It is a limited vasculitis of deep dermis or subcutaneous tissue caused by some reasons, often invades both lower limbs, and is more common on the inner side of calf. The disease occurs in young women, and generally has more onset in the cold season of autumn and winter. It manifests as bilateral symmetrical or bright red, dark red, or purple nodular lesions on the extremities, with significant pressure pain and generally no itching.
7.Nodular vasculitis
It is a lymphocytic infiltration-based small vasculitis of the skin that occurs in the lower extremities of adults. Small skin nodules occur repeatedly in the lower legs or feet, with normal or slightly red skin color on the surface of the nodules, spontaneous pain or pressure pain in the nodules, slow development, but sometimes with an acute course, and red and hot skin on the surface. The nodules are usually arranged along superficial veins, with mild pain or tenderness, and generally no systemic symptoms. Most ulcers do not occur and disappear in about 2 to 4 weeks or leave fibrous nodules, which disappear very slowly and can recur.
8.Hard erythema
Also known as Bazin’s disease. It occurs mostly on the flexor side of the calf of young women, and is a nodular mass, and the damage often breaks down. It is easy to develop in winter, so the disease is related to age, gender, cold and blood circulation status. Patients often have pulmonary, lymphatic, or other organ tuberculosis. Hard erythema with tuberculosis-like infiltration and often caseous necrosis has been thought to be a form of cutaneous tuberculosis, but Mycobacterium tuberculosis cannot be detected, so it is thought to be one of the tuberculosis rashes.
9.Thrombo-occlusive vasculitis
Thrombo-occlusive vasculitis is a systemic, non-suppurative, inflammatory disease of arteries and veins of unknown origin, mainly affecting the blood vessels of the extremities. It is common in young and strong males, with coldness, coldness, pain, numbness in the limbs, pain in the calves of the feet, intermittent claudication or even ulceration and gangrene of the extremities. When the patient is lying down and the lower limbs are elevated, the feet and lower legs are pale white, while the lower limbs are blue-purple or red when they are hanging low.
Generally speaking, it is not difficult to distinguish frostbite from other diseases when the disease manifests itself typically. For example, frostbite generally has the following characteristics: (1) It is extremely seasonal. The onset of frostbite is winter and spring, with the peak period corresponding to the winter solstice to spring, while damage from other diseases is heavy in winter and light in spring. (2) The onset of frostbite is closely related to the cold wave, and each attack is caused by poor warmth due to freezing. The local symptoms are numbness in the cold and itching in the heat, and are not usually accompanied by systemic symptoms. The ulcers heal and leave atrophic scars. (3) The frostbite damage site is fixed and consistent every year, with clear boundaries, no fusion, no expansion, and no extension. Progressive vascular filling time is significantly delayed. (4) The local rewarming of the skin is lower than that of the surrounding skin, and the rewarming after thermal radiation is higher than that of the surrounding skin. However, if the frostbite does not heal for a long time or does not heal for a long time, you should ask your doctor to find out the cause so as not to delay the condition. When you suspect that you have frostbite, it is best to ask your doctor to confirm the diagnosis before using medication.