These are the top five, based both on my medical knowledge and on my personal experience—I’m the queen of sensitive skin. I usually react to anything that’s not fragrance free. And since nonstop stress can make anyone’s skin sensitive, if you suddenly react to something, check product labels for these:

• Fragrance of any kind. Even if it’s the very last item on the ingredient list, meaning there’s only a tiny amount, it can be a problem for people like me.
• Cinnamates. They’re used in some sunscreens (where they’re usually listed as methylcinnamate) and lipsticks. Yes, they come from cinnamon but you’re not likely to have any problems with the spice, just this derivative.
• Lanolin and mineral oil. Lots of people react to these, although they’ve been around for centuries and remain fairly common ingredients in skin treatments. Lanolin is why some people have problems with Aquaphor, which otherwise is an extremely good moisturizer.
• Helioplex. It’s a relatively new sunscreen agent that does an excellent job at blocking both UVA and UVB rays, but I’d say 99 percent of the sunscreen rashes I saw during the summer of 2007, when it really hit the market, were Helioplex related. It reminds me of the problems with PABA, which worked well but also irritated so many people that it’s no longer common in sunscreens. They may find a way to solve the Helioplex reactions, though.
• Sorbic acid. It’s used in prescription retinoid creams as a preservative, but it’s a key reason that many people find them irritating at first.

If your skin reacts to one of these, it doesn’t mean all the others will bother you, too, or that nothing else will! I have to be careful with nearly everything on the list, yet sometimes I can use a product with fragrance. On the other hand, propylene glycol can get to my skin. You start to figure these things out for yourself. And sometimes a whole product line won’t agree with your skin, yet there’s no obvious reason why. I often have patients say, “You know, I just can’t wear brand X—am I crazy?” The answer is no. It’s not that uncommon.

From The Mind-Beauty Connection: 9 Days to Less Stress, Gorgeous Skin, and a Whole New You by Amy Wechsler.

If your skin is generally sensitive, you need to avoid the following ingredients in your skin care product:

• Isopropyl alcohol
• Sodium chloride

Surfactants such as:

• Sodium lauryl sulfate
• Sodium laureth sulfate
• Ammonium lauryl sulfate
• Soaps such as sodium tallowate or cocoate
• Salicylic acid
• Willow bark (the natural version of salicylic acid)
• AHA acids

Chemical sunscreens such as:

• Avobenzone
• Octinoxate
• Octisalate
• Homosalate
• Octocrylene
• Oxybenzone