A rash changes the appearance, and possibly the texture, of your skin. Most skin rashes are reactions to the environment, such as chemicals or cleaning products, or reactions to an underlying medical condition. If you notice a flat, brown rash on your neck that resembles age spots, there is one likely reason. Call your doctor immediately -- this type of rash, called petechiae, can signal a serious medical problem.
Age spots, also called liver spots, are flat areas on your skin that can be brown, gray or black. They can vary in size, and typically appear on areas exposed to the sun, such as your face, neck, arms and hands. Age spots are harmless and do not usually require medical attention. If any of your age spots change size, shape or color, see a doctor to rule out skin cancer. Prolonged sun exposure and the use of tanning beds might increase your risk of developing age spots as you get older.
The rash that most closely resembles age spots is called petechiae. This type of rash appears as flat areas of red, purple or brown, and is due to bleeding under the skin. Petechiae may look like a rash, and will not change color if you press on it with your fingers. Petechiae can appear anywhere on your skin, but usually shows up on areas where blood applies a great deal of pressure to your veins, such as your ankles or feet. The rash can appear on your neck in certain instances.
Petechiae on your neck might occur after a bout of vomiting. When you throw up, you can put excess pressure on the blood vessels in your face and neck, causing them to burst and lead to petechiae. Intense or prolonged crying may also cause petechiae. In these cases, petechiae is harmless and will fade on its own. The rash might also be caused by abnormal blood clotting in your cells, which could be because of a serious medical condition such as leukemia or rheumatoid arthritis. Neurofibromatosis, a genetic disorder that alters cell growth in your nervous system, or septicemia, a blood infection, are two additional medical conditions that can be characterized by the development of petechiae.
Call your doctor immediately if you develop a petechiae rash on your neck that resembles age spots. Even if you suspect the rash developed because of vomiting or crying, see your doctor to rule out any underlying medical conditions. Petechiae may also be a less common symptom of bacterial infections, and prompt treatment is essential. Take a digital picture of the rash on your neck and e-mail it to your doctor if you cannot get an immediate appointment. Alternatively, head to the emergency room, particularly if you have any other symptoms.