My face suddenly turned red and hot

Allergy is a disease that everyone is familiar with. Many people are prone to this disease because of their low resistance. Among allergic diseases, skin diseases are the most common. When some friends suddenly have a red and hot spot on their face, they may be suffering from a disease called allergic dermatitis. Treating allergic dermatitis is not difficult, but what causes allergic dermatitis?

Allergic dermatitis can be divided into many types according to the causes and clinical manifestations, such as drug allergy dermatitis, contact allergy dermatitis, photosensitive dermatitis, hereditary allergic dermatitis, autosensitive dermatitis, etc.

Allergic dermatitis generally occurs in patients with allergic constitution, and internal allergic factors play a leading role in the onset of allergic dermatitis. The instability of the internal environment, such as chronic digestive system diseases, mental stress, insomnia, excessive fatigue, mood changes and other mental changes, as well as infectious lesions, metabolic disorders and endocrine dysfunction, can all induce or aggravate allergic dermatitis. There are also many external factors that cause allergic dermatitis. Including factors such as diet, inhaled substances, climate, and contact with allergens. Among them, seafood, spicy food, alcohol, inhalation of pollen, dust mites, cold weather, contact with chemicals, soaps, detergents, etc. are the most common causes and triggers of allergic dermatitis. Due to such complex reasons, allergic dermatitis is prone to recurrence due to the interweaving of numerous causes and inducing factors.

Because the causes of allergies are different, the prevention and treatment methods are also different. Let’s analyze them one by one.

Drug allergic dermatitis is a body reaction and skin symptoms that occur in some sensitive patients after they have an allergic reaction to certain drug ingredients that enter the human body through various routes. If skin symptoms appear within a few hours to 2 weeks after using the drug, you should first consider drug allergy. You should stop the drug immediately and go to the hospital for diagnosis and treatment by a doctor. After confirming a drug allergy, you must remember the name of the drug you are allergic to, and tell your doctor when you get sick and seek medical treatment in the future to avoid using it, which may lead to another allergic reaction or even life-threatening.

As the name suggests, contact allergy dermatitis is an allergic reaction that occurs at the contact site after contact with certain substances. Common contact allergens include metals (eyeglass frames, belt buckles, watches, alloy necklaces, earrings, etc.), plastics (sandals, decorations, etc.), cosmetics, adhesive tape, etc. The characteristic of contact allergic dermatitis is that the disease occurs at the contact site, and some even have a special shape that is the same as the contact object. However, some contact allergies, such as cosmetic allergies, are difficult to diagnose and require patch testing to confirm the diagnosis. For people with allergies (those who have had various allergic reactions), it is best to try new cosmetics behind the ear or on the flexor side of the forearm for a few days before using them. If there is no redness or itching, you can buy and use them.

Photosensitive dermatitis is an allergic skin disease that occurs on the skin after exposure to sunlight in the presence of photosensitizing substances. Photosensitizing substances can be oral medications (such as tetracyclines, sulfonamides, etc.), foods (such as mud snails, gray vegetables, etc.), daily contacts (such as cosmetics, spices, preservatives, dyes in detergents, etc.), occupational contacts (such as tar, asphalt, etc.) or endogenous porphyrins, etc. For photosensitive dermatitis, the first thing to do is to try to find the photosensitive substance and avoid contact or consumption. Secondly, avoid sunlight and use UV-proof umbrellas and sunscreen. UV-protective parasols can block direct sunlight, but they are ineffective against sunlight reflected from the ground and walls, so be sure to use sunscreen at the same time. It is best to use sunscreen with PA++ and SPF15 or above, and reapply it at noon, otherwise the sun protection effect will be ineffective.

Genetic allergic dermatitis, also known as atopic dermatitis or atopic dermatitis, is related to genetic allergic constitution. It is characterized by itchy skin, polymorphic rash and a tendency to exudate, and has different clinical manifestations at different age stages. Patients often have asthma, allergic rhinitis and increased serum IgE. Infants may experience erosions, exudative lesions, and crusting on the scalp, forehead, neck, wrists, and flexor sides of the limbs. The condition may be severe or mild, and generally improves gradually within 2 years of age. In childhood, the condition usually starts to get worse around the age of 4. The skin lesions involve the extensor or flexor side of the limbs, often limited to the elbows and popliteal fossa, and the rash is thickened and lichenified. The itching is still severe. In young adults, it often occurs in the elbows, fossa, limbs, and trunk. The rash is often generalized dry papules or localized lichenified plaques. For patients with hereditary atopic dermatitis, in addition to oral antiallergic drugs and topical medications, they should also pay attention to food reactions and avoid allergic foods. Pay attention to environmental factors that aggravate the condition and try to avoid them. Avoid over-washing, excessive soap irritation and excessive scratching. Since the onset of the disease is related to dry skin and decreased barrier function, it is also important to use a topical moisturizer every day.

Autosensitivity dermatitis is caused by the patient's allergy to a substance produced by his own body or skin tissue components, and it can develop from a localized inflammatory focus to widespread dermatitis. There are often previous causes such as improper treatment or infection. Be careful to avoid irritating the primary lesion. If the primary lesion is obviously infected, antibiotics should be used.

In short, allergic dermatitis is prone to recurrence, and finding allergens and avoiding contact is the only way to prevent recurrence. Once the disease relapses, self-care after the onset of the disease is an important means for us to alleviate symptoms and shorten the course of the disease.