Get under the skin

With the cool air of winter upon most of us and cold, dry winds approaching, it’s time to get serious about caring for the stratum corneum, the outermost layer of skin, the body’s largest organ, which protects the vital tissues within.

Long thought to be biologically inert, the stratum corneum is now known to be an intricate, biochemically complex structure, the sanctity of which is critical to having healthy skin. It has a brick-and-mortar construction; the bricks — or corneocytes — are made up of organised threads of keratin that can hold large amounts of water, embedded in a mortar consisting of fatty acids and other lipids.

Skin, in fact, is 64% water, making water an essential ingredient of healthy skin. If the stratum corneum gets too dry, the skin can become itchy, scaly, inflamed, leathery and unattractive. For most people, whether their skin is dry or oily and especially if they live in a cold, dry or windy climate, routine use of a moisturiser can protect the skin’s water supply.

Spoilt for choice

But faced with the dizzying array of choices on store shelves, how is the consumer to select a moisturiser likely to be effective and unlikely to cause an unwanted reaction? Should you choose a lotion, cream or ointment? Should you look for one labelled “dermatologist-recommended,” “fragrance-free,” “non-comedogenic,” “organic,” “natural,” “clinically proven” or “hypoallergenic?” Do you make a selection based on brand name, price, a doctor’s or friend’s recommendation?

Those are good but hard-to-answer questions, says Dr Shuai Xu, a dermatologist affiliated with Northwestern University’s Feinberg School of Medicine. One of the most frequent complaints about skin care products like moisturisers is their all-too-common ability to trigger an allergic reaction, resulting in itchy, red, inflamed skin.

Dr Xu and colleagues recently evaluated 174 best-selling moisturisers of different types, with special attention to the presence of allergenic ingredients. Lotions were by far the most popular, accounting for 59% of moisturisers sold, followed by creams at 13%, oils at 12%, butters at 8% and ointments at 2%. The team found that only 12% of the best-selling moisturisers were free of allergens. The three most common allergens were fragrances, parabens and tocopherol.

Even among products labelled “fragrance-free,” 45% had at least one fragrance-related ingredient. Dr Xu said that if a company uses an ingredient that is both a preservative and a fragrance, it can still claim the product to be “fragrance-free” if preservation is the ingredient’s primary purpose.

Also, a product labelled “fragrance-free” or “unscented” could contain a masking agent, a cross-reactive chemical that acts like a fragrance, or a botanical ingredient that is an allergen, Dr Xu said.

Among the 15 products claiming to be hypoallergenic, 83% had at least one ingredient on the allergen list, and 24 products contained five or more such ingredients.

Fight allergies

Furthermore, as Dr Jonathan I Silverberg, who directs Northwestern’s Contact Dermatitis Clinic and Eczema Center, explained, “Much of the labelling of products as hypoallergenic is nonsense. If you use a product long or often enough, you can become vulnerable to an allergic reaction. It’s not that the product is mislabelled — it’s that you can become allergic to almost anything, especially if you have a predisposition.”

An initial mild allergic reaction of itching and redness can progress to a profound reaction of stinging, burning, swelling and pain, Dr Silverberg said. “With each exposure, the reaction gets stronger,” he said. Thus, the wise consumer with an allergic tendency might consider switching periodically to a different product and should certainly stop using any moisturiser that seems to be setting off an untoward reaction.

The American Academy of Dermatology suggests that in choosing a moisturiser, consumers wishing to avoid common allergic sensitisers pick one that is free of additives, fragrances and perfumes, though the new study showed this is clearly a challenge, even for knowledgeable physicians.

Cost is no guarantee of safety or effectiveness, the new study showed. Products labelled “dermatologist-recommended” are more expensive, but Dr Xu said “the label doesn’t mean anything — is it 100 dermatologists, 10 dermatologists or one dermatologist?” The most expensive moisturiser his team analysed contained the most allergens — a total of eight.

Health-conscious consumers turn to products labelled “organic” or “all-natural” for moisturising in hopes of avoiding synthetic chemicals. But these “are not necessarily unlikely to cause a reaction and may not be effective,” Dr Xu said.

Olive oil, for example, increases water evaporation from the skin, he said, adding that the oils likely to be most protective and free of allergens are sunflower oil, coconut oil and shea butter.

However, for most people, moisturising lotions, which contain more water than creams or ointments, are effective and least expensive. They evaporate quickly on the skin and do not leave a greasy feeling that many consumers dislike.

Nonetheless, people with dry skin might invest in a cream or ointment, the cost of which is reduced by the need to use less of the product. Creams contain more water than ointments and offer what the team called “a middle ground” for people who dislike the greasiness of ointments. Ultimately, the team concluded, “patient adherence and willingness to use a moisturiser is more important than a specific formulation or vehicle.”

Ideally, moisturisers are best applied on damp skin within minutes of bathing, after patting the skin dry, to lock in moisture. Also helpful is to bathe or shower in warm, not hot, water.