Doctor K: Allergy to latex defies explanation

DEAR DOCTOR K: I’m a nurse who is allergic to latex, so I always use latex-free gloves. But I still occasionally break out in hives. Why?

DEAR READER: A product may claim to be “latex-free” or state that it “does not contain latex.” But the truth is that no existing tests can show that a product is completely free from latex.

“Natural rubber latex” comes from the sap of the rubber tree. This material is used to make a host of stretchy products, including adhesive bandages, condoms, gloves used in health care and dishwashing, balloons, rubber bands, baby bottle nipples and more.

Natural rubber latex can cause an allergic reaction because it contains proteins that set off some people’s immune systems. A latex allergy usually occurs in people with repeated exposure to natural rubber latex. That’s why they’re more common in health care workers and frequent surgical patients.

Hives or welts are a common allergic reaction to latex exposure. So are swelling, a runny nose and sneezing; red, itchy or teary eyes; headache, sore throat, abdominal cramps; or chest tightness, wheezing or shortness of breath. Sometimes the reaction can cause anaphylactic shock, which can be deadly.

Not everyone who is latex-sensitive has hives or welts. Some people get contact dermatitis, consisting of a skin rash and itching that start one to several days after contact with a latex product. Over time and repeated exposure, contact dermatitis can cause dry, crusted scabs on the skin.

Synthetic latex is an alternative to natural latex. It doesn’t provoke allergies. You can (and should) use gloves made from synthetic latex. But even that’s not a guarantee, because products made without natural latex can be contaminated with latex proteins during the manufacturing or packaging process.