Cosmetics continue to be used by acne-prone individuals. Often as more acne develops,
more cosmetics are applied. In order to protect against this natural tendency, physicians
should provide more patient information on the currently available products and ingredients.
This presentation is designed to help in that effort. The data presented were gleaned
from the rabbit ear assay, which is not an ideal animal model but is the best we have.
If an ingredient is negative in the rabbit ear assay, we feel it is safe on the acne-prone
skin. A strong, positive ingredient or cosmetic should be avoided. Ingredient offenders
include isopropyl myristate and its analogs, such as isopropyl palmitate, isopropyl
isostearate, butyl stearate, isostearyl neopentanoate, myristyl myristate, decyl oleate,
octyl stearate, octyl palmitate or isocetyl stearate, and new introductions by the
cosmetic industry, such as propylene glycol-2 (PPG-2) myristyl propionate. Lanolins
continue to be a problem, especially derivatives such as acetylated or ethoxylated
lanolins. Our most troublesome recent finding is the comedogenic potential of the
D & C Red dyes. They are universally used in the cosmetic industry, especially in
blushers. This may explain the predominance of cosmetic acne in the cheekbone area.
All of these D & C Red dyes tested to date, the xanthenes, monoazoanilines, fluorans,
and indigoids, are comedogenic. Actually, this is not surprising as they are coal
tar derivatives. The natural red pigment, carmine, is noncomedogenic and can serve
as a substitute for D & C dyes in blushers. Many finished products are comedogenic.
Most troublesome to the dermatologists are the therapeutic tools that we use, such
as Liquimat, Retin-A cream, Hytone, Staticin, Sulfoxl, Desquam-X, and Persadox HP
cream. These should be reformulated. We have been unable to confirm that precipitated
sulfur (U.S.P.) is a potent comedogen in the rabbit ear assay. Clinically, we still
find sulfur quite effective as an adjuvant to the benzoyl peroxide therapy for the
treatment of acne vulgaris. We would suggest that the bias against sulfur be reconsidered.