The common causes of itchy bumps on the neck are contact dermatitis, hives, prickly heat and so on. 1. Contact dermatitis: Dust mites, willow flakes and pollen in the environment are common allergens. If you accidentally come into contact with these substances, it may lead to the appearance of red pimples the size of rice grains on the face, neck and other parts of the body, accompanied by itchy sensations. 2. Urticaria: Common causes include stimulation by food, drugs and sunlight, as well as mosquito bites and mental factors. The rash usually appears as small red bumps, which can occur in any part of the body and is accompanied by intense itching, and the disease is easy to recur. 3. Prickly heat: also known as heat rash, if you are in a hot environment for a long time, sweat a lot and do not pay attention to skin hygiene, it is easy to prickly heat, so that sweaty neck long small red bumps, and accompanied by itching and pain. In conclusion, there are many reasons for the itchy bumps on the neck, patients should go to the regular hospital in time, follow the doctor’s instructions for treatment, and keep the skin clean in daily life.