A red bag on the neck may be due to folliculitis, urticaria, insect bite dermatitis, lymphadenitis and other causes.
1. Folliculitis: generally due to hair follicle infection caused by staphylococcus aureus, streptococcus, etc. It is common in the head, face, neck, thighs and other parts of the body, and manifests itself as a red pimple around the hair follicle, which may be accompanied by pus, itching, pain and other symptoms.
2. Urticaria: Urticaria has a rapid onset, may be related to cold, sun exposure, some chemical stimulation and other factors, manifested as the appearance of varying sizes on the skin mass-like elevations, bright red or pale white, accompanied by obvious itching.
3. Insect bite dermatitis: local skin allergic and inflammatory reactions occurring after being bitten by mosquitoes and other local skin bites, commonly found on the face, neck, hands and other exposed parts, manifesting as sudden pea to finger-sized doughnut erythema, often with severe itching.
4. Lymphadenitis: If the lymph nodes in the neck are inflamed, resulting in enlarged lymph nodes, poor lymphatic reflux and the formation of a mass, the infiltration of inflammatory cells, can be to the end of the local redness and swelling of the symptoms.
A red bag on the neck may also be caused by other factors, it is recommended that patients seek medical attention in a timely manner in order to clarify the cause of the disease, targeted treatment.