It depends on the size of the package and where it happened. If it is part of the hair follicle, it may be because of folliculitis, which leads to folliculitis caused by bacterial reproduction. It may also be a benign lipoma formed by subcutaneous fat; It may also be caused by local swelling and blood stasis after trauma; It may also be due to the exudation of joint fluid from some joint cavities, resulting in cysts called tendon sheath cysts.

So I packed my bags.

This symptom is common in urticaria, which is a localized edema reaction caused by reactive expansion and permeability increase of small blood vessels in skin mucosa. The etiology of most patients is unknown, especially chronic urticaria. Common reasons are as follows:

1, food, mainly including animal protein, plants and some food additives, some of these substances can be used as allergens to cause hypersensitivity, and some can directly stimulate mast cells to release histamine.

2, drugs, many drugs are caused by hypersensitivity in the body, and some drugs are caused by histamine release.

3, infection, including all kinds of bacteria, fungi, viruses, parasites and other infections.

4. Physical factors.

5. Animal and plant factors.

6. Mental factors.

7, secondary to visceral and systemic diseases.

8. Other factors, such as inhalation, pregnancy or menstrual cycle.