Cosmetics, bacteria, brittle nails

Q: What cosmetics are best for the patient with recurrent facial MRSA?

It is unlikely that a patient would become reinfected from cosmetics that are purchased within the year they are manufactured by a large company. Most companies are careful to select product preservatives that will not support bacterial growth, since bacterial growth will destroy the cosmetic formulation by causing product separation or a foul smell. Yet, it may be worthwhile to make a few recommendations to the worried patient.

Cosmetics that can be self-renewed are the best. Products of this type include pencils and crayons where the cosmetic is plastic or wood encased and sharpened to reveal new cosmetic. Lipsticks, lip liners, eyeliners, and eye shadows are widely available in this form. The patient should sharpen the cosmetic prior to each use to prevent MRSA spread. The rest of the cosmetics applied to the face should be powders. Since powders contain no water, they cannot support bacterial growth. The powder should be applied with brushes that can be frequently washed with baby shampoo and allowed to dry. The only way the brush can support bacterial growth is if it becomes wet. Commonly available powdered cosmetics include mineral facial foundations, facial powder, blush, and eye shadow.

Cosmetic product precautions may not play much of a role in recurrent MRSA infection, but patients may feel more comfortable knowing that they are not using contaminated cosmetics. This reassurance from the dermatologist may be valuable.

Q: What do you tell the patient who continues to experience brittle nails following oral biotin supplementation?

A: Brittle nails seem to be more of a problem in individuals who wash hands frequently and in the elderly. Nails become brittle when the nail plate water content drops, since water is the most important nail plasticizer. Biotin supplementation may not be helpful in individuals with severe nail plate dehydration. Unfortunately, once the water is removed from the nail plate, it can never be fully replaced due to the nonliving nature of the nail.

The most common treatable cause of nail plate dehydration in my practice is habitual antibacterial waterless hand cleanser use. These infection-preventing gels contain a high solvent concentration that is damaging to the nail plate. Some individuals whip out their hand sanitizer every time they touch a doorknob or shake hands. My recommendation is they discontinue use of the waterless hand sanitizer and use a moisturizing liquid cleanser with water instead. They will get better microbe removal from the hands in most instances and less nail plate dehydration.

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 zdraelos@northstate.net
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