Yes, you really should wash new clothes before wearing them. Here’s why

In a post on TikTok, a woman showed pictures of her arms, legs and face covered in pink hives – a reaction, she wrote, that developed soon after wearing a new dress she bought online.

On Reddit, similar stories abound in posts about “itchy red bumps” and hives cropping up on people’s skin shortly after wearing new clothes.

Dr Susan Massick, a dermatologist at the Ohio State University Wexner Medical Centre, says it was common for her patients to complain about skin reactions to new clothes, especially in areas that experience friction such as armpits, groins, waists and necks.

We spoke with experts to find out what might be causing the irritation and whether washing new clothes before wearing them could help.

Why do new clothes cause reactions?

New clothes often contain a variety of substances that can irritate the skin or cause allergic reactions, says Dr Shamsa Kanwal, a dermatologist in Portland, Oregon.

Dirt and dust, which can accumulate in storage, may lead to a red, itchy or painful rash, she adds – particularly for those with sensitive skin. The most common causes of irritation, however, are the thousands of chemicals used during textile manufacturing, Kanwal says.

Many clothes are treated with various substances – like fungicides, chemical finishing agents and fragrances – that reduce wrinkling, extend shelf life, resist stains and mildew, and keep garments smelling nice, Kanwal says.

Not all of these substances will cause reactions, she adds, but dyes are a common culprit – especially azo dyes, which are often used on synthetic materials like polyester.

Formaldehyde (used to prevent wrinkles), pesticide residues (commonly found on clothes made from cotton) and fragrances can also cause an itchy, red rash in areas of close contact, Kanwal says.

In a 2022 study, researchers in Spain examined 120 pieces of baby, toddler and maternity clothing purchased from various retailers in Spain and online. They found formaldehyde in 20 per cent of the samples.

Even clothes labeled “organic” can still have dyes, finishing agents, softeners and fragrance, Kanwal says.

Does washing help?

Washing clothes before wearing them does help remove some potential irritants such as excess dyes, fragrances and formaldehyde, the experts we spoke with say. “In our tests, a single short washing cycle with cold water removed almost all of the formaldehyde present,” says Joaquim Rovira Solano, a researcher from the University of Rovira i Virgili in Spain who coauthored the 2022 study.

But not all problematic chemicals are completely removed by washing, says Sylvana Brickley, a nurse practitioner who specialises in dermatology at Lahey Hospital and Medical Centre in Burlington, Massachusetts. Many chemicals that can irritate the skin, like flame retardants and antimicrobial treatments used to prevent odour in some activewear, are designed to stay on clothes after multiple washes. People who are sensitive to such chemicals may have reactions, no matter how many times the clothes are washed, Brickley says.

For dry-clean-only items, steaming or airing them out before wearing them for the first time may help dispel some fragrance or other odours, Kanwal says, but it probably won’t help with other, more durable finishes like wrinkle-resistant resins, stain resistance treatments and some performance coatings. She suggests wearing a barrier layer, like a thin T-shirt, underneath new clothes that can’t go in the wash.

If a skin reaction persists after you’ve washed your clothes, Massick recommends consulting a dermatologist. Most often, she says, the reaction is irritant contact dermatitis – a typically short-lived red, itchy rash that shows up within minutes to hours after direct contact with a substance and generally doesn’t require treatment beyond avoiding the irritant.

A more troublesome and less common reaction is allergic contact dermatitis, which occurs when your body develops an allergy to a substance after repeated exposures to it. Even small exposures can cause reactions like an itchy rash, swelling, bumps, blisters, burning or tenderness, which can take two to four days to develop, Brickley says.

If you develop any type of rash from wearing clothes, Massick advises resisting the urge to itch, which can worsen the rash or cause skin discoloration or an infection.

At the end of the day, Brickley says, washing your clothes before wearing them can come with some drawbacks. Collars may not be as stiff, and colours may not be as vibrant. But “it all comes down to whether you want that stuff on your clothes or not,” she says.

The New York Times

Make the most of your health, relationships, fitness and nutrition with our Live Well newsletter. Get it in your inbox every Monday.