Yes, the vitamin A contained in an egg yolk, may help acne.

More Info: There are no studies directly linking egg yolk ingestion with fewer acne flare-ups, but egg yolks are a rich source of vitamin A.  Healthy skin is the first step in managing your acne, and getting your recommended daily allowance of vitamin A can help you toward that goal. 

Vitamin A in Egg Yolks Good for Skin

Vitamin A (retinol) plays an important role in the health of your skin. Retinol acquired through diet or supplementation supports the maintenance and health of skin and mucous membranes supporting their function as a barrier against viruses and bacteria.

Vitamin A and Acne Possible Link

One study, at least, has detected a possible link between vitamin A and acne.  In a study published in the British Journal of Dermatology, researchers set out to explore the link between the levels of vitamin A and carotenoids in patients with acne vulgaris.  The researchers discovered "that the mean serum concentrations of retinol and retinol-binding protein were significantly decreased in patients with acne." [Rollman, 113]

Topical Vitamin A Good for Skin

Many over-the-counter cosmetics, particularly skin care lines, contain vitamin A as the active ingredient in the form of retinal or retinoid.  The emerging anti-aging industry touts the benefits of Retin-A for treating fine lines and wrinkles, but this derivative of vitamin A has been used to treat acne for years.  The prescription drug Accutane is another vitamin A derivative and is taken orally as an aggressive treatment for cystic acne. ["ACCUTANE®(isotretinoin capsules)." DailyMed]

Eggs May Cause Acne?

Ironically, in a 2006 study of 166 acne patients, more than 42% believed  that eggs directly exacerbated their acne condition.  The list of perceived acne causing foods also included nuts, chocolate, fried foods, cakes, coffee, and tea. [El-Akawi, 840]