Eczema, solar dermatitis, herpes zoster or pityriasis rosea are the symptoms of many red spots on the neck. 1. Eczema is mostly allergy-induced, usually caused by skin contact with certain allergens to local or systemic allergic reactions. The main manifestation is the appearance of symmetrical erythema and papules on the neck, with obvious itching. 2. Solar dermatitis is an allergic reaction to ultraviolet rays in sunlight, mostly seen in summer and high latitude areas. It is characterized by large erythematous patches on the exposed parts of the skin, with obvious itching or pain at the erythematous patches. 3. Herpes zoster is caused by a viral infection that strikes when the body’s immunity is low. It manifests as scattered erythema on the neck unilaterally, with papules and blisters on the erythema and obvious pain. 4. The cause of pityriasis rosea is unknown, mainly related to immune system disorders, mostly seen in young people. Performance for the neck and trunk, limbs proximal end of the scattered erythema, erythema on a small amount of flaking, no obvious self-conscious symptoms. There may be other causes of erythema on the neck, it is recommended to go to the hospital in a timely manner, a clear diagnosis, symptomatic treatment.