Long-lasting red skin



Red skin rash, also known as artificial urticaria, is an allergic reaction to skin blood vessels. The formation of allergic reactions is caused by internal and external factors. There is a special protein in the serum of such patients, which is immunoglobulin IgE. When such proteins are combined with allergens, the body will cause a series of reactions, and finally the mast cells around the blood vessels of the skin will release a large amount of histamine. , histamine causes skin vasodilation, and serum oozes out of the blood vessels, causing itching. At this time, the skin scratch test is positive.



The long-lasting red skin is one of the symptoms of skin cancer. The onset of skin cancer may be related to the following factors:

(1) Excessive sun exposure, causing cancer due to large amounts of ultraviolet radiation.

(2) Ionizing radiation, such as a cancer worker who develops cancer due to long-term exposure to medium or small doses of radiation or the skin of a patient receiving radiation therapy.

(3) Frequent exposure to chemical carcinogens such as arsenic, polycyclic hydrocarbons, and asphalt.

(4) Severe burn scars.

(5) precancerous lesions: such as keratosis, xeroderma pigmentosum, chronic inflammation, skin atrophy after lupus, epidermitis retraction, etc.

(6) Immunosuppression.


an examination

Related inspection

Skin scratch test skin fungal microscopy

Diagnosis relies on biopsy, but the diagnostic is required to have sufficient experience to identify lesions that are suspected of being malignant. Highly suspicious early malignant lesions in the following situations:

1, skin ulcers that have been cured for a long time or when there is a good time or a small amount of bleeding.

2, where there are bleeding, ulceration or asymmetrical nodular protrusions in solar keratosis.

3, the skin or old sores that have been irradiated by radiation in the past, or ulceration or nodular protrusions at the sinus.

Biopsy in multiple lesions of multiple resection biopsy, diagnosis and treatment of a double-edged sword, complete its work. The lesion is slightly larger, especially if it needs to be removed, including 2 to 3 mm outside the lesion. If the normal skin can reach the treatment requirement, the defect is too large, causing the appearance defect. Then take the clamp or cut the biopsy, and remember to include the proximal part of the lesion.


Differential diagnosis

The differential diagnosis of red skin blemishes that have not subsided for a long time:

Keloid: Chinese medicine is called crab foot swelling or giant scar, which is a kind of fibroid. This disease is related to physical constitution and is a product of excessive proliferation of fibrous connective tissue. If the epidermis of the scar tissue is damaged, such as trauma, mosquito bites, vaccination, burns, folliculitis, hemorrhoids, etc., there is a high possibility of scar formation. pimple. Local factors include inflammation after trauma, foreign body irritation, and excessive tension. The keloid protrudes from the surface of the skin in a tumor-like hyperplasia, with a smooth surface, reddish color and brightening, and it is often found that the expanded capillaries extend outward. The skin is damaged to the outside of the edge, the crab feet are deformed, the skin damage is one size, the shape is different, the quality is hard, the symptoms are many, and it is itchy or stinging. Due to the acute pain, it may be caused by the conduction of nerve endings or the formation of microneuromas, even when the clothes are gently touched. The development is slower, but it continues to increase. Some patients occasionally have malignant changes (recurrently infected with ulcers), and keloids occur in the chest, shoulders, neck, back and auricle. Both men and women can happen.