Allodynia is pain from normal sensations such as touch or warmth. It may occur when a person is touched lightly or brushed gently across the skin. It also can occur from small changes in skin temperature. Many of the theories about how allodynia occurs point to nerve damage or malfunction from conditions such as migraines, shingles, fibromyalgia, and diabetes. The increased frequency and level of pain can have side effects such as fatigue, depression, and anxiety. Allodynia is different from hyperalgesia, in which normal pain becomes extreme. Pain from this condition is often completely unexpected at first. There are various causes and treatments of allodynia.
1. Static allodynia
Static or tactile allodynia occurs when someone is touched gently and directly, such as tapping on the shoulder, and he or she feels pain. It can make the person anxious and jumpy, leading to deliberate avoidance of touch and being near others who might touch them. It can occur on specific parts of the body, or over large areas, and can make the person seem “jumpy.” Static allodynia can be confusing at first, as the pain is unexpected. The sensitive area might correspond to a past injury.