What is the cause of the hard lump on the child's wrist?

The physical health of children is very important to parents. Once they find any abnormality in their children's body, parents will definitely be worried, fearing that their children have suffered from some serious illness. For example, children who often play outside are prone to develop hard bumps on their wrists, and their parents cannot find the cause. So what is the disease of a hard lump on a child's wrist?

Insect bite dermatitis, also known as infantile papular dermatitis or papular urticaria, is a common skin disease that occurs frequently in children. Children affected by the disease will develop red papules of uniform size or papular vesicular rash on their skin, which are itchy and restless and often linger and recur repeatedly. Because itching can make children cry and become irritable, if the skin is scratched, it may cause suppuration due to secondary infection. This disease is more common in infants and young children, and the incidence rate is higher in spring and summer. The prognosis of this disease is generally good. This disease is similar to water scabies in traditional Chinese medicine. Some scholars also call this disease vesicular ulcer.

Nowadays, it is almost universally believed that insect bite dermatitis is related to insect bites, and can be said to be an exogenous allergic reaction caused by arthropod bites. When a patient is bitten by an arthropod, such as bedbugs, fleas, mosquitoes, worms, etc., the insect saliva can be injected into the skin. If the person has an allergic tendency, then the disease may occur after several bites over a few days. Most people believe that it is a delayed hypersensitivity reaction. The reasons for holding the above view are: first, 90% of patients showed positive reactions in skin tests using antigens made from the above-mentioned insects; second, the months when the disease is most prevalent coincide with the seasons when insects love to bite people; third, patients are kept away from the environment that caused the disease and avoid contact with such insects, which often results in sudden recovery; fourth, if patients are bitten repeatedly over a long period of time, desensitization may occur. Therefore, the incidence of this disease gradually decreases with age after children reach the age of 7, until middle-aged people basically do not suffer from the disease.

In addition, some scholars have suggested that a small number of patients may be allergic to certain foods, especially proteins.

Symptoms and signs

(1) This disease is common in infants and young children, especially in summer and autumn. Sometimes several children in a family become ill at the same time.

(2) Typical skin lesions are mung bean-sized or slightly larger light red papules that are hard in nature and often have blisters on the top. They form scabs after being scratched and are surrounded by spindle-shaped red halos. Wheals appear after scratching, and return to their original shape after the wheals subside.

(3) It often occurs on the trunk and proximal limbs. The number of lesions is variable and they may appear in batches, scattered or in small clusters, often accompanied by gastrointestinal disorders. A small number of patients may also have blisters.

(4) The course of the disease varies in length. Generally, it will disappear on its own in about a week, leaving temporary pigmentation. However, new rashes may appear one after another, so that new and old skin lesions can be seen at the same time. The disease gradually heals when the weather turns cooler, but it often recurs the following year.

(5) The child experiences severe itching, which is particularly severe at night and often affects sleep, making the child restless. Scratching can cause the epidermis to peel off, which can easily lead to secondary infection.