Recently, I tried a new face cream. Big mistake. Within three days of starting to use it, I had a red rash across my face. I’d been so careful, too: I’d read all the ingredients, and nothing looked irritating. But there was the rash, red and itchy. I could mostly hide it with foundation. It went away in a few days, and my face looks normal now, but lesson learned. I have to keep reminding myself that I’m hypersensitive.

I didn’t understand that when I was young, which made life more difficult than it probably should have been. But when I was doing my PhD, I came across Elaine Aron’s The Highly Sensitive Person, and later I read Sharon Heller’s Too Loud, Too Bright, Too Fast, Too Tight, and in both I recognized aspects of myself.

What does it mean when I say that I’m hypersensitive? It means that when I buy creams and cosmetics, I look for those that say “for sensitive skin,” because I tend to react badly to certain chemicals. Like, Red Rash Zone. But I can’t go without face cream either, because I burn easily, and even the wind will make my skin red and itchy. I need to protect it. And natural products are often even worse than what I can buy in an average drugstore — Mother Nature, much as I love her, is a treasure house of irritants and allergens. I don’t react as badly as some people I know: I can wear perfume just fine, although strong smells bother me. As do loud noises. And violence.

Because hypersensitivity manifests itself in all sorts of ways: it means, I think, that you have fewer layers of protection from the world than most people. You are more vulnerable to it. This can be a strength: you notice things that other people don’t. If we were in a room, I would probably intuit your emotions, perhaps even what you’re thinking. I would know from the expression on your face, the way you’re holding yourself. But it’s also a weakness. Things that other people find energizing might exhaust you, if you’re hypersensitive. I find theme parks mildly horrifying.

Because I’m missing some of those barriers, I have to build them myself. Some of them are physical: my apartment, which is a sort of refuge from the world, beautiful and soothing. It has thick walls, and soft carpets, and light that filters in through large windows. Books and art and music. Even my face cream is a sort of barrier. But most of them, and the most important ones, are internal. I have to be able to, emotionally and mentally, find a peaceful center within myself, so I can live in a magnificent city, and teach at one of the best universities in the world. So I can interact with sixty students, being there for them without feeling as though I’m losing myself.

I don’t quite know how I build those internal barriers. I didn’t have them as a child, which made childhood incredibly difficult. Imagine if you’re a child, sensing the world so deeply, alive to beauty, but also every criticism. You live intensely — I still do, and I don’t want to lose that intensity of perception. It took a long time to build them, and some of them are unconscious now. (One of them is kindness, and another of them is politeness, and if you don’t know how kindness and politeness can be barriers, then pay attention the next time someone is being kind and polite. Pay close attention to how you’re being shut out.) But I know that those barriers are necessary . . . And I’ve once again learned my lesson about face cream!