Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Causes include everything from irritating foods we eat, to certain diseases, and infections. Treatment options include medicine including, local anesthetics, for example, lidocaine (Xylocaine), pramoxine (Fleet Pain-Relief), and benzocaine (Lanacane Maximum Strength), vasoconstrictors, for example, phenylephrine % (Medicone Suppository, Preparation H, Rectocaine), protectants, for example, glycerin, kaolin, lanolin, mineral oil (Balneol), astringents, for example, witch hazel and calamine, antiseptics, for example, boric acid and phenol, aeratolytics, for example, resorcinol, analgesics, for example, camphor and juniper tar, and Gas (intestinal gas) means different things to different people. Everyone has gas and eliminates it by belching, burping, or farting (flatulence). Bloating or abdominal distension is a subjective feeling that the stomach is larger or fuller than normal. Belching or burping occurs when gas is expelled from the stomach out through the mouth. Flatulence or farting occurs when intestinal gas is passed from the anus.
Noxious input to the spinal cord is known to produce central sensitization, which consists of allodynia , exaggeration of pain, and punctuate hyperalgesia , extreme sensitivity to pain. Two types of mechanical hyperalgesia can occur: 1) touch that is normally painless in the uninjured surroundings of a cut or tear can trigger painful sensations (touch-evoked hyperalgesia), and 2) a slightly painful pin prick stimulation is perceived as more painful around a focused area of inflammation (punctuate hyperalgesia). Touch-evoked hyperalgesia requires continuous firing of primary afferent nociceptors, and punctuate hyperalgesia does not require continuous firing which means it can persist for hours after a trauma and can be stronger than normally experienced. In addition, it was found that patients with neuropathic pain, histamine ionophoresis resulted in a sensation of burning pain rather than itch, which would be induced in normal healthy patients. This shows that there is spinal hypersensitivity to C-fiber input in chronic pain.