Your Medical History. By Dr. Peter W. Kujtan, B.Sc., M.D., Ph.D.

Most people are surprised to discover that skin is the heaviest organ in the body by weight. It wraps you up like a hug; it keeps your insides in and the outside out. Skin insulates you; it anchors your hair; it lets you feel and touch your surroundings. Skin is versatile; visible.

Your outward appearance depends on skin; yet, it falls off every 28 days. This surface layer contains tough keratin (same material as fingernails). This is the layer which resists day-to-day contact of living. Live oxygen-rich and nerve-rich lower epidermis layers migrate upward . The deepest dermis layer of skin has fibrous tissue which gives strength and shape to skin .

CSI-Miami is a fascinating (but, intensely surreal) crime-solving show. The unique fingernail patterns of skin had been the number one tool identifying criminals for decades (now DNA samples link the crime to the criminal). For primary care doctors, abnormal skin lesions are common complaints by patients.

Tom is a likeable, uncomplicated 12 year old boy living in a comfortable suburb of Toronto. He brings home straight A's from school, loves sports, math and has the faith about his world. Tom scraped his knee 3 weeks ago on a tennis court. His skin became tender with a small bump. A scraped knee is the signature of an active childhood. The usual result is a crusty brown scab and quick recovery in a few days.

Tom's parents brought him to the hospital when Tom started to limp. The emergency room doctor withheld antibiotics because Tom is allergic to Cloxacillin (the antibiotic of choice). Tom's skin infection progressed to a boil and required two "cut and drain" surgeries. He was sent home and cared for by visiting nurses from the Community Care Access Centre.

Tom's boil was a Staphylococci abscess which resolved slowly. Every patient is unique. The combination of a Tom's general health including nutrition, his genetic makeup and the bodily insult (in Tom's case stubborn bacteria on the tennis court) left Tom struggling to overcome an abscess.

The Emergency doctor did not want to risk an allergic reaction by giving antibiotics to clear the skin infection. This was despite Tom's now -swollen knee. The Doctor did not want to use a second-line or even third choice antibiotics because Tom had no signs of blood poisoning or septic knee. We hear more of antibiotic- caused intestinal side effects. For example, pseudomembraneous colitis is a bloody long-term diarrhea caused by the opportunistic growth of Clostridium difficile bacteria in the presence in certain antibiotics. This nasty bacterium produces colon-destroying toxins.

The decision tree for a doctor treating boils can be complex. The first fork in the road involves deciding whether the infection is CONGENITAL or ACQUIRED. Skin conditions are congenital (you are born with them due to your DNA) or acquired (you experience an invasive germ or trauma, or environment insult). A skin lesion can be either a local condition or part of a total body condition. Focused treatments are all that is necessary for minor rashes. Examples include iodine based washes, creams and anti-histamines. Mikael Gorbachev did not need treatment for his port-wine stain rash on his scalp.

More powerful treatments, including biopsies and surgeries, are needed for serious allergic and infectious rashes. Lucien Bouchard needed a major thigh amputation to control his flesh-eating necrotizing fasciitis. Patients such as military pilots with third degree burns have a real chance of death. Acne torments the teenage skin and self-confidence. Clearly skin cancer, the most common cancer, needs aggressive treatment. Therefore, see your medical doctor about any worrisome rash.

Tom is well. His knee is fully recovered. He is running around at school and plays his sports. Luckily, this blemish on his otherwise picture perfect life was only skin-deep.