This is an irritating sensation that makes you want to scratch. It's also called pruritus. It is often caused by dry skin and is common in older adults, as skin tends to become drier with age. Depending on the cause of it, your skin may look no different than usual or it may be inflamed, rough or have bumps. Repeated scratching can cause raised thick areas of skin that might bleed or become infected.

This is a genetic disorder. It happens when genes that manage cell activity mutate and create abnormal cells that divide and multiply, eventually disrupting how the body works. Medical researchers estimate 5% to 12% of them are caused by inherited genetic mutations that can't be controlled. More frequently, it happens as an acquired genetic mutation. Acquired genetic mutations happen over the course of the life. Medical researchers have identified several risk factors that increase your chance of developing it.

This is bleeding from a damaged blood vessel. Many things can cause it inside and outside the body. The types range from minor, such as a bruise, to major, such as bleeding in the brain. If external bleeding can't be stopped or internal bleeding is suspected, immediate medical attention should be sought.

These are antibacterial drugs derived from bacteria or molds or synthesized de novo. They have many mechanisms of action, including inhibiting cell wall synthesis, increasing cell membrane permeability, and interfering with protein synthesis, nucleic acid metabolism, and other metabolic processes.

These are sudden, brief, involuntary, painful contractions of a muscle or group of muscles. They commonly occur in healthy people, sometimes during rest, but particularly during or after exercise or at night. They usually occur in the calf and cause plantar flexion of the foot and toes.