INTRODUCTION
Collagen is an important natural component of our skin's structure. It is also present in our joints, bones and ligaments. In young skin, collagen is abundant and imparts plumpness to the face and other areas of the body, such as our hands. As we age, the amount and quality of collagen in our body decreases, and as a result, wrinkles and creases begin to appear. Our cheeks become hollow and our upper lip thins.

In the past few decades, the cosmetic industry has attempted to market creams and lotions containing collagen as virtual fountains of youth, but in fact, collagen works best when it is injected into the skin, not smeared on it. Applying collagen topically provides a slight boost to the skin's elasticity, but injecting collagen is much more effective.

Cosmetic surgeons use a form of collagen derived from cows (injectable bovine collagen) to correct imperfections that time has placed on our face. The bovine collagen is purified to create a product that is similar to human collagen. In this form, Collagen falls within the category of an "injectable soft tissue filler." When injected beneath the skin, these fillers plump up creased and sunken areas of the face. Collagen can fill out wrinkles, skin depressions and some scars. It cannot, however, correct severe wrinkles. Nor can it treat sagging skin. Other techniques such as a chemical peel, dermabrasion or a facelift may be needed to treat these other varied cosmetic concerns.

Allergy Testing Prior to Treatment
Before receiving collagen treatments, a patient should be tested on two separate occasions, at least two weeks apart, for a possible allergic reaction to the collagen. Doctors perform the second allergy test because most treatment-related allergic reactions occur after the first treatment. These "intradermal tests" are administered directly into the top layer of skin on the patient's forearm. A small amount of collagen is placed under the skin with a hypodermic needle. One may feel some minor stinging or burning as the injections are administered.

Patients should not exercise or drink alcohol on the day of the allergy test since these activities may produce swelling at the injection site.

Patients must return two days after the first allergy test and again four weeks later for an evaluation. At that time, the second test is given to determine if an allergy has developed as a result of the initial injection. Swelling, redness, tenderness or itching at the test site indicates that the patient should not receive collagen. This is only noted in 1-2% of the population.