Babies and Skin Allergies

What Is a Skin Allergy?

A skin allergy occurs when the skin becomes inflamed because of direct contact with an allergen, or when the body's immune system releases the chemical histamine in response to the presence of an allergen. When this happens, it causes an inflammatory reaction and can exacerbate eczema, hives, and other rashes.

"Younger infants and children, particularly those with a history of sensitive skin, eczema, asthma, or allergies, have hyperirritable skin," says Robert Sidbury, M.D., division chief of pediatric dermatology at Seattle Children's Hospital. "This means repeated wetting and drying can cause a rash that looks identical to a rash caused by a food allergy." The skin will often appear red, with tiny bumps, so it is easy to mistake common facial rashes for food allergies.

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Common Causes of Skin Allergies

First, determine whether the rash is caused by an allergen or by a simple irritant, Dr. Sidbury says. Baby's drool can cause an unwanted rash. Consult your pediatrician to determine possible allergies -- the best starting point is reviewing medical history, he adds. Usually this can establish the likelihood of a particular food or exposure as a true allergen. If an allergen is suspected, a doctor may recommend a skin prick test, where one needle (or more) is coated with a suspected allergen and then used to scratch or "prick" a spot on the arm or back. Here are the more common causes of skin reactions on your baby and what to do about them.

Drool

"Drooling leads to a rash right around the mouth and chin, so parents often think it's a rash caused by an allergy to food when it is simply a skin irritation," Dr. Sidbury says.

What it looks like... Redness and tiny bumps on the area that comes into contact with saliva. The rash is usually located on the mouth area, but it can extend down to the neck and chest.

What to do about it... "Try coating the area around the mouth with petroleum jelly before feeding, and then clean and apply another coat after the feeding," Dr. Sidbury suggests.

Drool rashes can be unsightly and uncomfortable, but generally they are nothing to worry about, unless a crusty yellow area appears on the rash; this could be a sign of infection. If you see this, consult your doctor right away. Otherwise, take heart: Once your baby stops teething, the drool should subside.

Food Allergens

If you've already eliminated irritants and the rash still persists, a food allergy could be the cause. "Eggs and milk are the chief culprits in very young children, but wheat, soy, and peanut allergies are not uncommon," Dr. Sidbury says. As kids get older, tree nuts and seafood can become a problem, along with environmental allergies such as grasses, trees, and dust mites, but there are no hard-and-fast rules as to when allergen can develop.

What it looks like... Flushed skin, welts, hives, and face, tongue, or lip swelling. If you do see swelling symptoms, your child could be experiencing anaphylaxis, a very serious allergic reaction that usually occurs almost immediately after the food is eaten. If your baby is having trouble breathing, call 911 immediately.

What to do about it... Blood test and skin prick tests are the most effective ways to test for food allergies, but false positives are common. "An 'allergy' is not simply diagnosed by a positive test," Dr. Sidbury says. "An allergy is an abnormal reaction to a food or an environmental stimulus, plus an abnormal test." If you have ongoing concerns about your baby's skin, consult your pediatrician, who can advise you about further tests and refer you to a pediatric dermatologist if needed.

• Food Allergies and Your Baby's Skin

Soaps, Lotions, and Detergents

It's not uncommon for babies, who have sensitive skin, to have a reaction to certain cleansers, moisturizers, and laundry detergents, which contain potentially irritating chemicals.

What it looks like... A red rash or skin irritation, especially after your baby is bathed, has lotion applied, or wears just-laundered clothes.

What to do about it... Try switching the lotion or detergent to a different brand, particularly one that is fragrance-free. When using new lotions, apply a small amount to your baby's skin and wait a few minutes to see if there's a reaction; otherwise, doctors recommending applying moisturizers immediately after bathing. Make sure to use a mild detergent to wash the clothes of everyone in the household, as well as linens or anything that may come in direct contact with your baby's skin. Sometimes an allergy may take a while to appear, so even if you don't see a reaction to lotions or detergents on your baby's skin right away, keep an eye on her skin over the few days.

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