A, the key to desensitization lies in skin structure and skin defense;

B, dry, oily and mixed skin may become sensitive skin;

C, desensitization cannot rely on cosmetics and ointments containing hormones;

D, desensitization with vitamins is not enough;

E. Allergy is a prelude to chloasma, acne and erythema.

Allergic skin should be carefully cared for, not dead skin;

Internal causes of allergies

1, skin structure is damaged;

2, the skin immune and protective function decreased.

Allergic external cause

1, exposed to wind, cold, heat, spicy, sun, excitement, scratching, oppression, seafood, cosmetics, bites, dust, pollen, cold water, etc.

2. All kinds of fake and shoddy cosmetics or cosmetics that are not suitable for you;

3. After peeling Chinese herbal medicines or chemicals;

4. Long-term external use of ointment or cosmetics containing hormones;

5, oily skin or acne after healing damage to the skin.

Skin itching is a common symptom of human body. Sometimes it comes from external factors, such as parasites such as lice and fleas and pests such as mosquitoes and flies, and sometimes it comes from diseases inside the human body (including the skin itself). According to the degree of itching and its accompanying symptoms, the following diseases can be judged.

● Mild itching

The itchy skin has a hemispherical rash as big as a grain of rice and as big as a pea, which is hard at the initial stage and gradually softens at the later stage. After picking, white cheese-like substances can be squeezed out, mostly infectious molluscum.

If there is a cap needle or a slightly larger flat papule on itchy skin, the surface is smooth and often broken, which may be flat wart.

If there is a small erythema on itchy skin, it will soon form pustules with redness around it. Scratching can spread the infection to other parts of the body and produce new pustules, which is often pustulosis.

If skin itching starts from hoary head and then spreads downwards, making dandruff increase like bran, or there is no obvious erythema, it may be seborrheic dermatitis.

If itchy skin appears on cheeks, neck, elbows, liquid pits or outside limbs, and most of them are localized erosion, the skin lesions are symmetrical or polymorphic, which can be diagnosed as eczema.

If skin pruritus is paroxysmal, with ants walking and burning sensation, and often induced or aggravated by the stimulation of mood, temperature and clothes, these symptoms may be skin pruritus.

If the skin itching starts from the scalp or limb extension, the skin lesions are covered with silver scales, and after peeling off the scales, a reddish translucent film and punctate bleeding can be seen, which should be thought of.

Psoriasis.

If skin itching occurs in hot summer, and it is located under the forehead, neck, elbow fossa, trunk and female breast, it is initially a small red papule with a dense needle tip, and soon becomes a small blister or pustule, the size of which is like millet, and most of them are prickly heat.

● Severe itching

If the skin of feet or hands is itchy, sometimes it is blister type, chafing type or scaly type, it is often tinea manus and pedis, among which tinea manus and pedis is commonly known as "goose's paw wind" and tinea pedis is commonly known as "beriberi". Such as finger joints, wrist flexion, axillary front edge, elbow flexion, inner thigh, female breast, lower abdomen, male genitals and other places of skin itching. (Children can also see it on the face and head), and there are five red rashes and blisters, and black lines can be seen. Such symptoms may be scabies.

If skin itching first occurs in the neck, or in the eyes, face, sacrum, limbs and vulva, flat round or polygonal solid papules gradually appear, accompanied by slight desquamation, it may be neurodermatitis, which is called psoriasis, stubborn tinea and neck sore in Chinese medicine.

If there are wheals at the itchy skin, which have different shapes and sizes, they occur quickly and subside quickly, and sometimes they can attack many times a day, which may be urticaria.

● Tickle.

Itching is a scratching disease, also known as artificial urticaria. The symptoms of this disease are similar to other types of urticaria, including severe itching and wheal on the skin, but the most striking feature is that scratching the skin with fingers is unbearable. The so-called appearance of skin blisters refers to the appearance of red or reddish blisters on the skin. They developed rapidly, but they also disappeared quickly, leaving no trace after retirement.

To distinguish skin scratches from other urticaria is to do a positive skin scratch test by hand. You can also scratch your skin with a blunt instrument. If wheal lesions appear at the scratching site and disappear after 10 minutes, or a word is scratched on the patient's back, the wheal that appears is the shape of the word, indicating that the patient must be dermatoglyphics rather than other urticaria.

At present, the cause of the disease is not clear, and Antaile is the first choice for drug treatment. Patients can go to the hospital dermatology department for further diagnosis and treatment.

Itching is generally thought to be caused by skin diseases, but some itching, especially obvious, persistent or recurrent itching, without any rash occurring first or at the same time, is often a signal of many diseases.

-itchy skin, suggesting that it may be caused by obstructive jaundice, diabetes, thyroid disease, etc.

-some chronic nephritis, entering uremia stage, can appear itchy skin all over the body.

-Patients with neurasthenia and cerebral arteriosclerosis often have paroxysmal itching.

-itchy anal skin, suggesting that there may be hemorrhoids, anal fistula, anal fissure, proctitis, intestinal parasitic diseases and other diseases.

In addition, there is no history of itching at ordinary times, and intractable itching suddenly appears. Generally, there is no change in the skin surface, but there is unbearable itching, which has nothing to do with the climate. Any antipruritic drug is ineffective. At this time, we should be alert to the possibility of cancer and must go to the hospital for further examination in time. For example: itchy nostrils are often the unique manifestations of brain tumors; Rectal cancer and sigmoid colon cancer, often manifested as anal pruritus; All kinds of leukemia, lung cancer, esophageal cancer, etc. It itches all over. Therefore, this kind of itching has attracted the attention of foreign experts. According to foreign research data, itching often occurs before cancer appears and has been regarded as a precursor symptom of cancer.

● Pubic pruritus

① Female pudendal pruritus: There are many diseases that cause female pudendal pruritus, which are briefly introduced as follows:

Trichomonal vaginitis This is vaginal inflammation caused by microbial trichomonas infection. Its common symptoms are increased leucorrhea, yellowish and dirty color, smelly foam, sometimes milky white or yellowish white liquid, sometimes yellow-green purulent foam leucorrhea, followed by vulvar itching and burning pain.

-Fungal vaginitis. This disease is vaginal inflammation caused by mold infection. The main symptoms of this disease are increased leucorrhea, watery or curd-like, ointment-like, or white flake and crumb-like, bean curd residue-like, severe vulvar itching, burning pain, fidgeting and abnormal pain.

-Senile vaginitis. Vaginal inflammation caused by postmenopausal vaginal atrophy and pathogen invasion and reproduction is more common in elderly women. Increased leucorrhea, pruritus vulvae, burning sensation or discomfort caused by pelvic uplift are common accompanying symptoms.

-Leukoplakia vulvae. This is a special form of chronic inflammation, which mainly proliferates on the mucosa of female external genitalia or on its adjacent skin surface. The etiology of vulvar leukoplakia is chronic inflammatory stimulation, such as chronic vaginitis, pelvic inflammatory disease, cervicitis, long-term secretion increase, vulvar dampness, local stimulation, pathological changes and so on. Mechanical stimulation, such as wearing hard tights for a long time and other mechanical friction, frequent and endless sexual intercourse. The change of sex hormones and chronic epithelial malnutrition can lead to the disorder of vulvar epithelial activity and lead to white lesions.

Pubic lice disease Some women find that the inner thigh or waist is a bluish-gray patch as big as a broad bean, and the pressure does not subside. Persistent scratching can cause local eczema, erosion, exudation, scabbing and other phenomena, sometimes secondary folliculitis and long-term itching. If this symptom is not cured for a long time, it may be a sexually transmitted disease-pubic lice disease. Pubic lice have a pair of slender front legs and two pairs of hooked claws, which can firmly grasp the root of pubic hair or attach to the surface of pubic mound, and spread directly during sexual contact, and a few can also spread indirectly through underwear, mattresses or bedpans.

It is not easy to be found that crabs parasitize the roots of pubic hair for a long time. Looking at it with a magnifying glass, you can find some small granular yellow spots and rusty or reddish lice eggs. This is a remarkable sign that distinguishes it from the eggs of whitehead lice.

Pubic lice disease not only exists widely in rural areas, but also has been found in many big cities in recent years. Because its rash is sometimes not obvious, and many people don't know the disease, or are embarrassed to let doctors check it, they are often delayed or misdiagnosed.

-pseudo condyloma. Pseudo condyloma is more common in women aged 20-30, and its rash mainly occurs in the medial labia minora and vaginal vestibule. The rash is white or reddish aggregate granular, similar to fish eggs, with smooth surface and granular touch. Some are filiform, papillary and polypoid. Most patients have no conscious discomfort, and some feel local itching. Pseudo condyloma patients usually have increased leucorrhea, which is white or five-color transparent, and generally has no obvious odor. In order to distinguish it from condyloma acuminatum, 5% can be used in rash.

Acetic acid coating, if it doesn't turn white, is pseudo condyloma, otherwise it is condyloma acuminatum. In addition, you can also check the human papillomavirus antigen, and all pseudo condyloma patients are negative.

The etiology of pseudo condyloma is not clear, and some people think it is physiological variation or related to the presence of candida in vulva and vagina. Others think that pseudo condyloma is caused by chronic diseases, which may be the result of long-term stimulation of vaginal secretions.

Diabetes. Diabetes mellitus is a systemic disease characterized by the continuous increase of blood sugar, which has a high incidence, disability and mortality, so it is considered as one of the main diseases threatening human health.

Typical patients show symptoms of "drinking more, urinating more, eating more and losing weight", that is, "three more and one less".

Others, such as vitamin A and B deficiency and low ovarian function, can cause vulvar itching. In addition, there is itching caused by mental factors.

2 male genital itching: not only female genital itching, but also men often encounter this unspeakable pain. In addition to crabs, there are four types of male pudendal itching:

Eczema scrotum In the acute stage, this eczema has red skin with small papules, and then it proliferates, infiltrates, erodes, oozes, cracks and itches. This disease is caused by damp-heat in liver meridian, so it should be treated by clearing heat, expelling wind and removing dampness. Chronic stage is often complicated with blood deficiency and wind dryness, so it is advisable to nourish blood and dispel wind. It is also effective to apply 1 egg white and 50g mung bean to the affected area.

Allergic dermatitis. This dermatitis is often caused by wearing chemical fiber underwear, drugs or diet. Most of the local lesions are erythema, eczema and dermatitis. It is unbearable to show itching. Once the allergen is found, stop using it immediately to avoid contact again. For this dermatitis, skin soothing cream and 20% camphor ointment can be used for external use. Oral antihistamines and calcium agents are commonly used.

Scabies This kind of sore is caused by scabies, and it is often infected by collective contact with scabies patients such as family or unit visitors. It can occur in penis, scrotum and inner thigh, and the rash is papule or herpes, which often shows bean-like induration after scratching. It gets hotter at night, which often affects sleep. Scratches and scabs may also occur due to scratching, and secondary infection may occur, resulting in pustules and furuncles. If the treatment is difficult, you can choose sulfur ointment or other drugs;

Tinea cruris It is limited to the inner thigh near the genitals and buttocks, and it is a fungal skin disease. The skin lesion is a coin-shaped erythema with papules, blisters, scabs and scales at the edge, which heals in summer and winter. Various tinea potions can be used for treatment.