Is Your Skin Lactose Intolerant?

A couple of weeks ago, we rounded up our favorite milk-based beauty products in honor of the advent of this rising-star ingredient. It's gaining popularity for good reason: Milk contains lactic acid, which has proven itself to be a superior skin-softening agent.

But, one astute commenter raised a question we hadn't considered. If your skin reacts poorly when you ingest milk products, will dairy-based skin care cause acne flare-ups and irritation, too? To answer the question, we turned to dermatologist Dr. Whitney Bowe and allergist Dr. Julie Kuriakose.

According to both doctors, there are essentially three tiers of milk reactivity. First, there are those who self-diagnose a connection between dairy and some sort of adverse response, like breakouts. Then, there are people who suffer from lactose intolerance, which can cause symptoms like an upset stomach. Finally, there are those who are truly allergic to milk and have the most severe reactions — think hives, shortness of breath. "For people with an actual allergy, even just having milk touch their skin can trigger a reaction," says Dr. Kuriakose.

It's for this reason that people diagnosed as allergic should stay far, far away from milk-based beauty products. But, according to Dr. Bowe, "True milk allergies are extremely rare in adults. Milk allergy does not equal lactose intolerance, and lactose-intolerant people should, in theory, have no problem using milk products on their skin."

So, there you have it. People who are lactose intolerant by way of digestion or who have found a connection between the physical intake of dairy and skin flare-ups do have the green light to apply milk topically. "The dairy-acne connection stems from digestion of the milk triggering a cascade of hormonal events that ultimately leads to acne," says Dr. Bowe. "That cascade is not triggered by applying product to the skin." Phew! But, Dr. Kuriakose suggests taking caution: "It may be safe, but do a trial. Try it on an area other than your face, like back behind your ear."

But, wait — what if you've got stubborn breakouts, and you're unsure if dairy could be the culprit? It's tough to diagnose, says Dr. Kurikose, because few studies have been done on the subject. However, just as she does for patients with allergies and sensitivities across the board, she suggests keeping a journal detailing what you're eating — and in this case, how your skin is behaving — to determine a possible link.

And, it's important to note that even if you're not plagued by dairy-inflicted skin irritation now, it's still a possibility down the road. "There's a whole realm of people with milk sensitivities because, as we age, we start to lose the enzymes capable of digesting milk," says Dr. Kuriakose. "It's not as uncommon as people think. Most non-white — Asian, African-American, Latina — adults have some form of lactose intolerance, depending on dosage." And that, she says, is because their ancestors didn't integrate dairy so drastically into their diets as Caucasians.

We're not saying to swear off milk entirely, but when it comes to acne, half the battle is identifying the cause. So, the takeaway here is to approach dairy with cautious optimism — because milk can only do a body good if it's right for you.

H2O+ Milk Moisturizing Body Balm, $12, available at Beauty.com.