Scabies is a skin disease, which is caused by skin infection bacteria. Scabies is a troublesome skin disease. This kind of scabies needs long-term treatment and is contagious. Scabies can't be in contact with other people's skin, and there will be infectious symptoms.

1. Scabies: Also known as scabies and sores, it is an infectious skin disease caused by human scabies parasitic on the skin, which often occurs in thin and tender parts of the skin such as fingers, wrists, armpits and external genitals. The main manifestations are erythema, papules, papules and tunnels, accompanied by itching at night. Most patients can recover after treatment, but if they still don't pay attention to personal hygiene after treatment, they may relapse in a short time. Scabies is mainly caused by human scabies mite parasitizing human body. It can be spread through close physical contact, or through the use of bedding, clothes, towels, etc. With infected people. Scabies can survive on the surface of clothes or other objects for 2~3 days at room temperature after leaving the human body.

Second, the basic cause: sarcoptic mites are 0.2~0.4 mm in size and are generally parasitic on the skin surface. After fertilization, the female worm burrows into the stratum corneum of the skin, eats the stratum corneum tissue, digs a tunnel under the skin and lays eggs in it. After the eggs hatch, the larvae will crawl out of the skin surface, hide in the mouth of the hair follicle, and then gradually spread to other parts of the body. In addition to digging tunnels in the stratum corneum, sarcoptic mites will also cause mechanical stimulation to the body, and the excrement, secretions and corpses they produce will also cause allergic reactions and make the skin itch.

Third, typical symptoms

1. Onset site: Adults are mostly located in finger joints, wrists, cubital fossa, armpits, around navel, lower abdomen, genitals, groin, inner thighs, buttocks, and breast folds. Finger joints are the most common, and the head and face are generally not involved. In addition to the above-mentioned parts, the seams of infants' palms, soles and toes are also very common, and can also invade the head and face.

2. Typical manifestations: the patient's skin often has severe itching, and its symptoms are more serious at night because of the strong activity of sarcoptes at night. The lesions showed needle-like papules, papules and blisters, which were symmetrically distributed. Among them, the papule is reddish or normal skin color with redness around it, and the papule is a small blister at the top of the papule. Tunnels are common in finger joints, with gray-white or light black lines and swelling after bending, which is a unique symptom of scabies.

3. Other manifestations: Some male patients may have nodules in scrotum and penis, which are reddish or reddish brown, ranging in size from mung bean to soybean, usually accompanied by severe itching, called scabies nodules. When the body is sensitive, the skin lesions are extensive and accompanied by bullae. Norwegian scabies mostly occur in patients with weak body or low immune function, such as AIDS or chronic leukemia. It is characterized by large rash area, dry scab, serious infection, a large number of scales at the finger (toe) end, swelling between fingers, thickening of nails, bending deformation, dry alopecia, local lymph node swelling and special smell.