<Things you should know> Correct knowledge about "chilblains" (1) Explanation of the causes and symptoms of "chilblains" About chilblains (frostbite) Causes and mechanisms of chilblains (frostbite) Main symptoms of chilblains (frostbite) Chilblains, which can appear on hands and feet as the weather gets colder, are a common problem. This article, supervised by a dermatologist, provides a detailed explanation of what causes chilblains, what symptoms they cause, and what other conditions can present with similar symptoms. About chilblains (frostbite) Chilblains (frostbite) are a condition where symptoms appear on the extremities of the body due to cold. First, let's explain the terminology for chilblains (frostbite). What is chilblains (frostbite)? Chilblains are medically known as frostbite. They cause swelling of the fingertips, toes, earlobes, etc., which can turn red to reddish-purple, and may be itchy and slightly painful when pressed. This condition occurs when blood vessels constrict due to exposure to cold, leading to poor blood flow. Difference from frostbite Frostbite, which can occur during winter mountain climbing, is a condition in which exposure to sub-zero temperatures impairs blood flow to the extremities, such as the fingertips and toes, causing the skin tissue to freeze and be destroyed, sometimes leading to necrosis, or causing hypothermia due to a drop in body temperature and impaired blood flow throughout the body. While frostbite occurs in sub-zero temperatures, chilblains (frostbite) occur at above-average temperatures of 4°C to 5°C. The difference between cracks and chapped skin. Cracks and chapped skin are symptoms that occur on the fingertips during the dry winter months, but these are actually a type of eczema called progressive palmar and plantar keratoderma, caused by the loss of sebum due to dryness and washing dishes, and are different from chilblains (frostbite). Causes and mechanisms of chilblains (frostbite) Chilblains (frostbite) are more likely to occur in environments with an average temperature of 4-5°C and a daily temperature fluctuation of around 10°C. Therefore, they are more likely to occur in early winter and at the end of winter when the daily temperature fluctuation is greater than in the middle of winter, and can occur even in people living in warmer regions. In recent years, the number of patients has decreased due to improved airtightness of houses and heating systems that warm the entire interior, but they are still common in school-aged children, and can recur even in adulthood, especially in women who do a lot of housework involving water. Cold weather can impair blood flow to the fingertips and toes, causing swelling, congestion (stagnation of blood flow), and in severe cases, blisters. It is also characterized by itching, which worsens when the affected area warms up or during bathing. However, the onset of the condition is not solely dependent on temperature; sweating and genetic factors also play a significant role, and the exact mechanism of its onset remains unclear. Main symptoms of chilblains (frostbite) Chilblains (frostbite) can be broadly divided into two types depending on the condition of the affected area: the persimmon type (T-type), where the entire affected area swells like a ripe persimmon and turns reddish-purple, and the polymorphic exudative erythema type (M-type), where multiple red, raised, swollen areas occur. There are also cases that are intermediate between the T-type and the M-type.In all cases, it is accompanied by itching, often described as "painful and itchy." In severe cases, it can lead to blisters or ulcers (a condition where the skin breaks down and becomes deeply eroded), and ulcers can become infected with bacteria, further worsening the condition. Areas where chilblains (frostbite) are commonly seen Chilblains (frostbite) commonly appear in the extremities of the body, which are easily exposed to cold. Specifically, these include the following areas: fingertips and toes earlobe The tip of the nose cheek kneecap From the elbow down (forearm) A disease that presents with symptoms similar to chilblains (frostbite). The following conditions may present with symptoms similar to chilblains (frostbite): Systemic lupus erythematosus It is a disease that is common in young women and is one of the autoimmune diseases of unknown cause (a disease in which the immune system, which protects the body from foreign invaders, attacks the body's own tissues).Red swellings resembling chilblains (frostbite-like erythema) can appear on the palms of the hands, soles of the feet, and fingers and toes. Since symptoms can be triggered by cold, it can be difficult to distinguish it from chilblains based solely on skin symptoms on the hands and feet. In the case of systemic lupus erythematosus, a characteristic erythema (butterfly rash) often appears on the face, and hair loss may also occur. In addition to skin symptoms, various symptoms can appear in internal organs such as the kidneys, lungs, digestive tract, and brain. Therefore, if the symptoms of chilblains are severe or recur frequently, it is recommended to consult a dermatologist and undergo a thorough examination, including blood tests. Sjögren's syndrome Like systemic lupus erythematosus, this disease is an autoimmune disorder that is common in women in their 30s to 50s, and it presents with symptoms similar to chilblains (frostbite) on the face and below the knees (lower extremities). Other characteristics include dry skin, dry eyes, and dry mouth. If symptoms appear outside of winter, you should undergo a thorough examination. Raynaud's disease, Raynaud's phenomenon Cold weather or mental stress can suddenly cause the fingers and toes to turn pale, and then red or purple. This condition may be accompanied by numbness or pain, and is more common in young women. It can occur as an underlying symptom of another disease (Raynaud's phenomenon), or it can occur as a standalone condition (Raynaud's disease). Cryoglobulinemia Cryoglobulins are abnormal proteins that solidify at 4°C and melt at 37°C. A condition in which these proteins increase in the blood is called cryoglobulinemia.In cold environments, symptoms such as purple bruises (purpura), ulcers, and joint pain may appear on the hands and feet, and symptoms affecting organs throughout the body are also common. It can be caused by underlying diseases such as multiple myeloma, or it can occur for unknown reasons. sarcoidosis Sarcoidosis is a disease of unknown cause that affects multiple organs in addition to the skin. The symptoms that appear on the skin vary, but in the diffuse infiltrative type, lesions that closely resemble chilblains appear in areas prone to frostbite, such as the nose, cheeks, ears, and fingers and toes. For this reason, it was formerly called chilblain-like lupus. The difference from chilblains is that there are no subjective symptoms and it can occur even outside of the cold season. Athlete's foot Athlete's foot is a common name for an infectious disease medically known as tinea. It generally refers to a condition where a fungus called dermatophyte proliferates on the feet (tinea pedis). The soles of the feet and the spaces between the toes become red, small blisters form, and the skin may peel. It is caused by factors such as prolonged dampness inside shoes, and the symptoms tend to worsen in the summer and improve in the winter. Underlying medical conditions to be aware of The following conditions can make you more susceptible to severe chilblains (frostbite), so caution is advised. diabetes In diabetes, blood vessels narrow or become blocked, leading to poor blood flow in the hands and feet, causing them to feel cold and numb. Furthermore, any wounds that form can easily become infected, leading to more serious complications. arteriosclerosis obliterans This disease is more common in men over 50. It is caused by blockages in the blood vessels of the legs, leading to poor blood flow and symptoms such as cold and numb feet. As it progresses, pain may be felt even when walking, and tissue necrosis may occur, requiring amputation. It is often associated with underlying conditions such as diabetes, high blood pressure, dyslipidemia, and obesity. Supervised by: Dr. Yuki Horiuchi, Director of Akihabara Skin ClinicAfter graduating from the Faculty of Medicine at Tokyo Women's Medical University, she worked at dermatology and cosmetic clinics in Tokyo before opening Akihabara Skin Clinic in 2007. She is a certified specialist of the Japanese Dermatological Association, a director of the Japanese Society for Medical Hair Removal, and an advisor to the A-Care Association. She is a member of the Japanese Dermatological Association, the Japanese Society for Aesthetic Dermatology, the Japanese Society for Laser Medicine, and the Japanese Society for Anti-Aging Medicine, among others. We take care to post accurate information,Please point out any incorrect information. Please submit any comments regarding medical information here. Return to the list of guides categorized by health symptoms.