Brown spots on the neck may be caused by sun spots or seborrheic keratosis. 1. Sun spots: sun spots are mainly caused by excessive exposure of the skin to the sun, which can occur in the face and may also occur in the neck, the main manifestation is that there will be brown spots in the local area, and redness, swelling, burning, pain and other symptoms may occur. 2. Age spots: also known as seborrheic keratosis, usually seen on the face and limbs and other exposed parts, may also appear in the neck, this disease is related to old age, sun exposure and other reasons. It is recommended to actively go to the regular hospital to do the relevant examination to make clear what the specific causes are, and then according to the situation to adopt the corresponding solutions. Avoid blindly using medication on your own, so as not to cause adverse consequences.