Q How do the "no nick" razors work?
A The "no-nick" razors work by coating the sharp spring-mounted blade with a fine gauge wire.
This is known as a wire wrapped blade. The wire functions to keep the blade off the skin surface preventing the novice shaver from cutting the skin. While the wire prevents skin damage, it also prevents a close shave. For this reason, the "no-nick" razors are best for children who are learning to shave where a close shave is not required. The wire wrapped blade is also recommended for elderly patients with a hand tremor or coordination difficulties.
A Under-eye circles are a perplexing problem for the dermatologist.
There are many causes of under-eye circles, some treatable and others difficult to remedy. The most common untreatable cause of under-eye circles is genetically inherited deep dermal pigmentation, frequently found in individuals from India. The best way to diagnose this type of under-eye darkness is to ask the patient for a family history. It is also impossible to treat under-eye circles that result from the optical shadows created by deep-set eyes. However, under-eye circles that are due to periorbital edema are readily treatable with long-acting antihistamines, such as Zyrtec (Pfizer). This type of under-eye circle has a characteristic bluish-gray color distinguishing it from the dark brown hyperpigmentation associated with familial hypermelanosis or the black color associated with deep-set eyes. There are individuals who have light brown pigmentation under the eyes similar in appearance to melasma. This more superficial pigment can be improved through the use of hydroquinone, but irritation is frequently encountered. My recommendation is to apply the prescription hydroquinone without other penetration enhancers followed by a heavy petrolatum in water moisturizer (Eucerin cream, Beiersdorf).
Q How is skin elasticity measured?
A Many cosmetic products entering the marketplace claim to increase skin elasticity.
This is a rather usual claim because highly elastic skin may also have so much flexibility that it easily falls into folds around the face. Increased skin elasticity is thought to be desirable because the skin recoil time following stretching is decreased. An assessment of skin elasticity on the back of the hand is frequently used to evaluate skin age. The skin on the back of the hand is pinched and then released. Highly photoaged skin will remain in the pinched position with slow recoil due to the loss of collagen and elastin fibers. Youthful skin will snap back to its original position almost immediately. At present, a variety of noninvasive bioengineering machines have been developed to simulate this test.
Skin elasticity assessments are typically performed with a suction cup device. An adhesive circle is attached to the rigid cup and then to the skin for testing. A vacuum machine is activated and released three times to create a graph of the tension required for skin stretching and the resulting relaxation curve. The evaluation of the curve is an indication of the skin elasticity. It is generally felt that well moisturized skin is more elastic than poorly moisturized skin, thus skin elasticity is usually related to claims regarding the effect of a moisturizer on the skin.
Zoe Diana Draelos, M.D., is a clinical associate professor of dermatology, Wake Forest University School of Medicine, Winston-Salem, N.C., and primary investigator, Dermatology Consulting Services, High Point, N.C. Questions may be submitted via e-mail to firstname.lastname@example.org.