Skin sensations, such as burning, numbness, itching, hyperesthesia (increased sensitivity) or tingling, with no apparent physical cause (idiopathic). The most common locations of paresthesias are the hands, arms, legs and feet, although paresthesias can occur anywhere on the body. Additional Info: There are many possible causes of paresthesia - too many to list here. Some examples include: (1) Physical nerve damage. (2) Inadequate blood supply to the affected region. (3) Pressure on the spinal nerves (e.g. herniated disk, tumors). (4) Carpal tunnel syndrome or other repetitive stress injuries. (5) Various long-term medical conditions (e.g. diabetes, underactive thyroid, migraine headaches, multiple sclerosis). (6) Transient ischemic attack (temporary and focal loss of cerebral function, "ministrokes"). (7) Stroke ("brain attack"). (8) Certain medications. (9) Toxic action on nerves, such as that from lead, mercury or arsenic. See also: Poison and Neurotoxin. A common cause of unexplained skin irritation is getting chemicals on yourself without realizing it. For example, if a small amount of a substance was spilled and not cleaned up, someone might later rest their arm or hands on the spill area and be exposed without realizing it. In addition, those who are sensitized (allergic) or have chemical hypersensitivity can exhibit symptoms even on exposure to trace amounts of certain subtances. If you notice any of the symptoms of paresthesia or have other unexplained medical issues, you should See: Your doctor for a physical examination and treatment. MSDS Relevance: Paresthesias can appear on an MSDS as a symptom of exposure to a number of toxic substances such as lead, mercury or arsenic, neurotoxicants, or skin irritants. Use appropriate personal protective equipment (PPE) such as gloves, aprons, goggles, dust masks etc. as necessary to prevent contact or exposure. Follow good chemical hygiene and clean up all spills promptly and completely. See also: Irritant, Sensitizer, Urticaria