According to allergists, people do not have a “chlorine allergy” but rather a reaction to chlorine. Chlorine reacts with your skin cells, leaving a layer of chlorine on the surface of your skin. (Technically, this is a layer of chloramines but people say "chlorine" so I'll use that word here). You may notice that you smell like chlorine? That’s because you are still covered in chlorine. Chlorine reactions may include itchy, red skin or itchy bumps -- the same things we call chlorine allergy. See also Chlorine Itch. Fortunately, the answer is pretty simple: do a better job washing the chlorine off of you after swimming.
The American College of Allergy, Asthma, and Immunology (ACAAI) posed this question: Can you be allergic to chlorine? Their answer: No, but you can be sensitive or have a reaction. See also, Chlorine Sensitivity.
“Chlorine reactions may include itchy, red skin or hives (itchy bumps). This is not an allergy but is actually "irritant dermatitis" (like a chemical burn), caused by hypersensitivity to this natural irritant. Chlorine is also drying to the skin and can irritate existing dermatitis.”
“Chlorine may indirectly contribute to allergies by irritating and sensitizing the respiratory tract. Studies have suggested that frequent swimming in chlorinated pools and exposure to cleaning products containing chlorine may increase the risk of developing asthma and other respiratory allergies, both in adolescents and in adults.
This is most detectable in people with long-term exposure, including lifeguards, professional cleaners, and swimmers with more than 1,000 hours of exposure. Many Olympic swimmers have suffered from chlorine sensitivity, found relief and gone onto win numerous medals, like six-time U. S. Olympic gold medalist Amy Van Dyken and five-time Australian gold medalist Ian Thorpe.”
The article lists the following symptoms of chlorine sensitivity:
Notably “Hives (urticaria) share some of these symptoms (itchiness and redness), but with raised patches or bumps with well-defined edges. Hives may appear suddenly and may grow in size.”
Skin sensitivity is typically treated by washing the affected area with clean water to try to remove any traces of the remaining irritant, i.e., cleaning product or swimming pool water.
Notice that the cure for “chlorine allergy” is getting the chlorine off of your skin. This seems simple but many people rely on ordinary shower products to wash away the chlorine. Those products do not get the chlorine off of your hair and skin.
** After swimming, your hair and skin would be better off if you washed away the chlorine. To do this, just use SwimSpray after swimming.