There is a wide variety of factors that can cause an itchy neck rash, including infectious, allergic and other culprits, according to Healthgrades. Some of the most common causes of a neck rash include an allergic reaction, inflammation, eczema or a bacterial infection.
If a neck rash occurs suddenly, it is likely the result of an allergic reaction, advises Healthgrades. The sensitivity can be a result of exposure to food, jewelry, clothing or other environmental factors. These types of rashes are often red and very itchy.
The most serious causes of a neck rash are bacterial meningitis, a severe reaction with anaphylaxis or cellutitis, warns Healthgrades. Cellulitis is a skin infection caused by invasive bacteria, and it is often accompanied by an itching, painful rash.
Numerous infections can cause an itching rash on the neck, according to Healthgrades, including chicken pox, measles, shingles and folliculitis. Since some skin infections are contagious, it is important to seek the care of a health care professional to avoid spreading the rash to other people. To help the doctor make a proper diagnosis, it is important for a patient to explain how and when the rash occurred, if the rash has spread to any other areas and any other symptoms that accompany the rash.