What causes itching?

In late autumn, the climate in the north has changed a lot, our skin will become very dry, and the number of people suffering from pruritus will continue to increase, many of whom are middle-aged and elderly people. Normally, you will feel unexplained itching on your body, and the more you scratch, the more itchy it becomes, even until your skin is broken, but the itching is still there. So what is causing the itching?

Skin itching is a symptom of many skin diseases. If you have symptoms of itching on your body, you should promptly understand the causes to see if it is caused by some skin diseases. As for what causes itching on your body, today we will look at what causes the symptoms of skin itching.

Systemic pruritus (pruritus universalis) is often associated with certain systemic diseases such as diabetes, uremia, hepatobiliary diseases, visceral tumors, blood diseases, thyroid diseases, allergic diseases, intestinal parasites, habitual constipation, irregular menstruation, pregnancy, mental anxiety, neurological diseases, etc. The pruritus of Hodgkin's disease is persistent, sometimes accompanied by a burning sensation. The incidence of pruritus is 10% to 25%, and it is the first symptom in 7% of patients, but the cause is unclear; more than 1/3 of patients with polycythemia have pruritus, which is often triggered by temperature changes and has nothing to do with histamine levels; 20% to 50% of patients with obstructive jaundice have pruritus, and the intensity of the pruritus is sometimes parallel to the bile salt concentration in the skin. Since the carboxylic acid level in the patient's central nervous system is elevated and naloxone treatment is effective, the pruritus may be caused by a central mechanism; patients with uremia also often have systemic unbearable pruritus, which may be related to certain metabolic imbalances; 3% to 47% of patients with systemic pruritus are found to have visceral tumors. Abnormal skin condition and function (such as dryness, atrophy, etc.) and climate changes (such as heat, cold, etc.) can cause itching; contact with dust, glass fiber, dust mites in daily work and life, eating certain spicy and irritating foods, and certain close-fitting clothing can cause systemic itching. Systemic pruritus can also be caused by drugs, such as opioids, niacin, antidepressants, cimetidine and certain central nervous system stimulants.

The cause of localized pruritus (pruritus localis) is sometimes the same as that of systemic pruritus. For example, diabetes can cause both systemic pruritus and localized pruritus. Anal pruritus (pruritus ani) is often related to enterobiasis, prostatitis, hemorrhoids and anal fistula, scrotal pruritus (pruritus scrotal) is often related to local hyperhidrosis, friction and tinea cruris, while vulvar pruritus (pruritus vulvae) is mostly related to leucorrhea, trichomoniasis, vaginal fungal disease, gonorrhea, diabetes and cervical cancer. It may also be caused by endocrine disorders, low sex hormone levels and menopausal autonomic dysfunction.

[Clinical manifestations] Depending on the scope of itching, this disease is divided into systemic and localized types.

1. Patients with systemic pruritus experience paroxysmal itching all over the body, and the itching often moves from one place to another. The degree of itching varies. Some people can bear it, while others feel severe itching and need to scrub their skin with an iron brush or wash it with hot water until the skin bleeds and feels pain and burning. The itching will be temporarily relieved. It often worsens at night and affects the patient's sleep. Due to severe itching and constant scratching, secondary skin lesions such as scratches and blood scabs may appear on the skin all over the body. Sometimes there may be eczematous changes, lichenification or pigmentation. Scratched skin is prone to secondary bacterial infection.

Systemic pruritus can be divided into:

(1) Pruritus senilis: It is usually caused by factors such as decreased secretion function of sebaceous glands, dry skin and degenerative atrophy, and is more common on the trunk.

(2) Winter pruritus (pruritus hiemalis): It is triggered by cold weather and is often accompanied by dry skin, which is aggravated by undressing and sleeping.

(3) Summer pruritus (pruritus aestivalis): High heat and humidity are often the triggers, and sweating often aggravates the pruritus.

2. Localized pruritus refers to itching occurring in a certain part of the body, which is common in clinical practice:

(1) Anal pruritus: the most common. The disease can occur in both men and women, but is more common in middle-aged men and in children who are infected with pinworms. The itching is often localized around the anus, sometimes spreading forward to the scrotum and backward to both sides of the buttocks. The skin around the anus is often grayish white or pale white with ulcers, thickened anal folds, and radiating fissures due to scratching. Secondary infection sometimes occurs. Over time, the skin around the anus thickens and becomes lichenified, and pigmentation may also occur.

(2) Vulvar pruritus: It mainly occurs on the labia majora and labia minora, and may also occur on the mons pubis and clitoris. Due to itching, the patient often scratches, and the vulva skin becomes thickened and grayish white. The clitoris and vaginal mucosa may become red, swollen and eroded.

(3) Scrotal pruritus: The itching occurs in the scrotum, but may also spread to the penis or anus. Due to constant scratching, the scrotal skin becomes thickened, pigmented, and lichenified. Some patients may experience erosion, exudation, crusting, and eczema-like changes.

What causes itching on your body? Now you should know what is going on. Don’t scratch it with your hands when it itches. Some people will get infected after scratching their itchy skin, and the skin will become worse. Therefore, we must do some care work, take a bath frequently, and go for timely check-ups to avoid the occurrence of some serious diseases.