Itching

Introduction Pruritus is a subjective sensation that can cause immediate aspirations. It is the most common common symptom of skin diseases. Due to the difference in various skin diseases and the third degree of individual, the severity and degree of itching can be light and heavy, and can be complicated, pulsating and persistent; it can also be localized, generalized or systemic. Those with itching light can reduce the loss after being scratched. Itching is serious, itching and unbearable scratching until the epidermis is broken and bleeding occurs when the first long pain occurs. Because of the constant scratching, the skin of the affected part can be thickened, and the thickened skin lesions aggravate the itching and form. The more itching, the more itchy, the more itchy.

Cause

It is currently believed that itching and pain are transmitted through a common neural pathway, and the occurrence of itch is the same as pain, which is stimulated by the free god at the junction of the epidermal dermis. Contact with the brain through incoming and outgoing neural reflexes. Whether the stimulus is foreign, intrinsic, reactive or reflexive in the range of itching can induce a feeling of itching.

A basic but physiologically active medium between the stimulus that causes itching and the impulse that occurs at the free nerve endings. Histamine is the material basis for itching. Any factors that lead to stimulation of mast cells, such as allergic, physical, and mental, can degranulate mast cells to release histamine. Therefore, the use of antihistamines and stable mast cells to reduce histamine release can be used to treat itching caused by histamine.

Peptides are hydrolyzed proteins, and in allergic skin diseases, bradykinin may also be a medium for producing itching and wheal. Prostaglandins and their related substances, human skin inflammatory cells are associated with arachidonic acid metabolites. These substances include prostaglandins, polymorphonuclear leukocyte chemotactic factors, and white diene. It has been found that prostaglandin itself does not cause itching, but it can reduce the threshold of skin-induced itching caused by histamine. Thereby making itching worse. Whether leukocyte chemotactic factors and leukotrienes can enhance the itching caused by other inflammatory mediators remains unclear.

Environmental and local factors can directly affect the skin's sensitivity to itch irritation, skin temperature is slightly increased, and the feeling of itching increases. Such as hot water bathing, room temperature is too high, after roasting fire or exercise can stimulate the nerve endings to cause itching, the humidity in the air is too complete to cause dry skin can also cause itching. This situation is more pronounced in older people. Mental and emotional instability can also increase the sensitivity of itching. Spicy food, drinking, coffee can cause itching. In addition to a lot of skin diseases caused by itching, some systemic diseases can also occur itching, such as uremia when itching is related to a certain circulating factor in the body, obstructive jaundice can cause intractable itching. In short, the mechanism causing itching is more complicated, and the clear mechanism is still not very clear.

There are many kinds of skin diseases that cause itching. Because the individual's severity and degree of damage are not the same. Even the same type of skin disease patients feel different degrees. Even the same type of skin disease patients feel different degrees. The cause of itching is complicated, and some causes are still unclear. Now, the common pruritus or severe itching skin diseases are classified as follows.

(1) Infectious skin diseases

Viral skin disease

Chickenpox, measles, flat warts, etc.

2. Bacterial skin disease

Pustular herpes, folliculitis, etc.

3. Fungal skin disease

Head lice, hands, athlete's foot, body lice, femoral hernia, tinea versicolor, etc.

4. Parasitic and animal skin diseases

Hookworm dermatitis, schistosomiasis dermatitis, rash, rickets, mosquito bites, mites dermatitis, mulberry dermatitis, hemorrhoids, etc.

(two) physical skin disease

Scorpion, polymorphic sun rash, sun dermatitis, frostbite, frictional mossy rash, etc.

(three) allergic skin disease

Contact dermatitis, eczema, atopic dermatitis, atopic dermatitis, fat dermatitis, drug eruption, pityriasis, etc., papular urticaria.

(four) neurological dysfunction skin disease

Neurodermatitis, scrapie, pruritus, nodular pruritus, pregnancy pruritus, exudative discoids, and dermatitis.

(5), scarlet fever-like erythema

Polymorphic erythema, psoriasis, parapsoriasis, pityriasis rosea, red pityriasis, pregnancy papular inflammation, lichen planus, cirrhotic atrophic moss, erythroderma, etc.

(6) herpetic skin disease

Herpes-like dermatitis, bullous pemphigoid, gestational herpes, herpes-like impetigo, subarachnoid pustulosis, continuous acral dermatitis, palmoplantar pustulosis, etc.

(7) Metabolic skin disease

Amyloidosis of the skin, mucus edema, and the like.

(8) Lymphatic reticular tumor

Mycosis fungoides, sexary syndrome, Hodgkin's disease, follicular lymphoma, mast cell hyperplasia, cutaneous white blood disease.

an examination

Related inspection

Skin smear microscopy physical examination of skin diseases

Itching is the main symptom of many skin diseases. It has no itching in the symptoms. It helps to diagnose certain skin diseases. Allergic skin disease, neuropsychiatric skin disease, itching is more intense, such as eczema, urticaria, drug eruption. , neurodermatitis, scrapie, pruritus, etc. However, skin damage such as syphilis, leprosy, and tuberculosis has no symptoms of itching. Apes and certain skin benign and malignant tumors also have no itching. Some hereditary, pigmented, keratotic and other skin diseases are generally not itchy or mild. If the itching is severe and there is no primary skin diagnosis, in addition to skin scrapie, it should be considered whether there is a systemic disease. Such as endocrine disorders, mycosis fungoides, mast cell hyperplasia of lymphoma.

Physical examination: The sign of itching is that there are different levels of scratches. Chronic itching can be seen because the skin is thickened and the pigment is deepened, but itching is heavier and there is no scratch. Because the patient's itching method is not necessarily scratching or scratching, it does not produce scratches, so the scratch is not diagnosed. The only basis for itching.

Differential diagnosis

Winter scrapie is more common in adults over the age of 40, and the lower extremities are particularly severe. These people have weakened sebaceous glands and dry skin. In the winter, bathing takes a long time, using more soap and making the skin drier. As the temperature drops, itching begins.

Itchy itch: The main consideration is the foreskin balanitis. In general, patients with itchy itch are caused by bacterial infections, and the climate is humid. They usually do not pay attention to their personal hygiene. Infection causes balanitis, which causes itching of the glans. An erythema or small papule appears on the glans of the penis. The glans has an itchy odor and the glans has a milky white viscous shape.

Itching of the scrotum: usually caused by scrotal eczema, allergic dermatitis, hemorrhoids, etc. Scrotal itching is a very common manifestation, especially for young men. The skin of the affected area is flushed. There are small moles, with erosion, oozing and fissures, and itching.

Itchy nose: refers to the symptoms of itching of the nose, accompanied by nasal congestion, nasal discharge, sneezing and so on. Its nasal itching is lighter than pollen symptoms. In addition, nasal eczema, nasal vestibulitis can also have nasal itching, accompanied by skin lesions.

Anal eczema itching: a type of secondary itching. Secondary pruritus is caused by primary diseases and various skin diseases, with obvious specific skin lesions and primary lesions. Itching is often a symptom of primary lesions. Such as anal fistula, anal eczema, genital warts, neurodermatitis, anorectal tumors, aphids and other anal itching are such. Initial anal itching is lighter, there is no obvious change in the anus skin, mostly paroxysmal. Itching is more frequent in patients with chronic illnesses, and lasts longer, especially at night. Excessive scratching or mechanical stimulation makes the perianal skin hypertrophy and rough, anal folds deepen, local scratches, blood stasis, exudate, wrinkles In the residual fecal dirt, even more severe can be combined with infection with pus or purulent secretions, flushing and swelling. The lesion can be extended to the perineum, scrotum, female vulva and even double-hip skin.

Itching of the scalp, especially when it is strenuous exercise or when the head is heated. Examination revealed that very small white crystal eggs were attached to the roots of the hair. It is different from dandruff and cannot be easily removed. Common in head rickets.

Vulvar itching: It is a symptom caused by various vulvar lesions, but it can also occur in patients with completely normal vulva. It is more common in middle-aged women. When the itching is aggravated, the patient is more restless, which affects life and work. Vulvar itching is mostly located in the clitoris, labia minora. It can also affect the skin lesions of the labia majora, perineum and even the perianal area. Frequent paroxysmal attacks can also be persistent, generally exacerbated at night, and no cause of genital itching usually occurs only. In the childbearing age or postmenopausal women, the whole genital area, but may also be limited to a certain part or unilateral vulva, although the itching is very serious, even unbearable, but the appearance of local skin and mucous membranes is normal, or only because of scratching Excessive scratches.

Itching is the main symptom of many skin diseases. It has no itching in the symptoms. It helps to diagnose certain skin diseases. Allergic skin disease, neuropsychiatric skin disease, itching is more intense, such as eczema, urticaria, drug eruption. , neurodermatitis, scrapie, pruritus, etc. However, skin damage such as syphilis, leprosy, and tuberculosis has no symptoms of itching. Apes and certain skin benign and malignant tumors also have no itching. Some hereditary, pigmented, keratotic and other skin diseases are generally not itchy or mild. If the itching is severe and there is no primary skin diagnosis, in addition to skin scrapie, it should be considered whether there is a systemic disease. Such as endocrine disorders, mycosis fungoides, mast cell hyperplasia of lymphoma.

Physical examination: The sign of itching is that there are different levels of scratches. Chronic itching can be seen because the skin is thickened and the pigment is deepened, but itching is heavier and there is no scratch. Because the patient's itching method is not necessarily scratching or scratching, it does not produce scratches, so the scratch is not diagnosed. The only basis for itching.

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