Aren't synthetic brushes safer for people with allergies to pet hair?

Yes. Most people with allergies to animals can find using traditional cosmetic brushes potentially irritating. As a makeup artist, I would often meet customers who had skin redness or irritation and never dreamed it could be caused by their cosmetic brush. Using man-made fibres helps avoid this important sensitivity issue. One educational insitution [The American College of Allergy, Asthma & Immunology], specializing in allergies, estimates that 10% of the general population are allergic to animal hair. That's over 30,000,000 Americans.