Washing bedding and pillows: how often, and why your skin cares

You spend roughly a third of your life pressed against the same few square metres of fabric. Everything your skin and hair give off at night ends up there, and some of it stays. Here’s what actually builds up in bedding, how often it’s worth washing, and when hot water makes a real difference.

What builds up in your sheets and pillowcases

A bed is warm, a little humid, and constantly supplied with food for tiny creatures. Every night your sheets collect:

• Sweat, the salty water your skin releases to cool you down, even on cool Canadian nights.
• Sebum, the natural oil from your skin and scalp, plus whatever leave-in hair products and night creams you wear.
• Dead skin cells. Your skin sheds its outer layer continuously, and those flakes settle into the fabric.
• Dust mites, microscopic relatives of spiders. Allergy UK explains that they feed on the dead skin cells we shed and prefer warm, humid conditions, which is a fair description of a bed.

For most healthy people, none of this is dangerous. It’s simply the reason old bedding smells stale and looks greyish. But for people with sensitive skin, eczema or allergies, what’s in the fabric can matter more than what’s in the detergent.

How often should you wash sheets and pillowcases?

There’s no law of nature here, but there is a consistent recommendation. Health Canada’s advice for reducing dust mites is to wash linens in hot water weekly. Allergy UK also suggests washing all bedding that isn’t in a protective cover every week.

Weekly is a sensible default for sheets and pillowcases. You might wash more often if:

• you sweat heavily at night or it’s the middle of a humid summer
• a pet sleeps on the bed
• someone in the bed has eczema, a dust mite allergy or asthma
• you’re recovering from an illness or a skin infection

And if you have no allergies and a week slips into ten days? That’s not a health crisis. The point is a steady routine, not perfection.

Duvets, blankets and mattress pads collect the same things more slowly because a top sheet or cover sits between you and them. Washing them every few months, or when they’re visibly soiled, is a common practical approach, though we couldn’t find a formal standard for it.

Does water temperature matter?

It depends on what you’re trying to remove.

For everyday grime, sweat and oil, a modern detergent at the temperature on the care label does the job. Heat isn’t what makes clothes clean anymore; the formula is.

For dust mites, temperature matters a lot. In a well-known 1992 study published in the Journal of Allergy and Clinical Immunology, all mites were killed by water at 55 °C or hotter. None of the detergents or laundry additives tested made cooler water kill more mites. A cold wash, with or without detergent, left most live mites in the bedding, although it did wash away more than 90 percent of the mite allergen (the protein in their droppings that causes allergy symptoms).

That’s why allergy clinics in the UK recommend a 60 °C cycle for bedding. Allergy UK explains the catch with cold washing: the allergen dissolves and rinses out, but the surviving mites simply produce more.

A practical note: a washer’s “hot” setting doesn’t always tell you the actual water temperature. If dust mites matter in your household, check your machine’s manual for a cycle that states its temperature. If you don’t have a mite allergy, there’s no need to run every load hot.

Pillows: the part people forget

Pillowcases get washed. Pillows often don’t, for years.

A small UK study in the journal Allergy cultured 10 pillows that had been in regular use for between 1.5 and more than 20 years. Every pillow contained fungi, with 4 to 16 species per pillow, and the most common was Aspergillus fumigatus, a mould that can cause lung problems in people with weakened immune systems or asthma. Synthetic pillows grew more species than feather ones. It was only 10 pillows, so it’s not a survey of every bedroom, but it’s a good reminder that a pillow is not self-cleaning.

Your options, from allergy clinic guidance:

• Wash the pillow if the care label allows it. Cambridge University Hospitals suggests a 60 °C cycle for pillows, quilts, blankets and duvets that aren’t in allergy covers.
• Freeze it. The same NHS guidance suggests that if a pillow can’t be washed, 12 hours in the freezer once a month kills dust mites. Freezing kills mites but doesn’t remove their allergen, so a wash afterward helps if the label allows.
• Use a zip-up allergen-proof cover that fully encloses the pillow, in line with the NHS trust’s view that barrier covers are the single most effective dust mite measure.
• Replace it when it’s lumpy, stained or smells no matter what you do.

Bedding, acne and eczema: what the evidence says

Does changing your pillowcase clear up acne? The idea is logical. The American Academy of Dermatology points out that oil from your hair can cause acne on your forehead and advises keeping hair away from your face. A pillowcase holds hair oil and product residue against your cheeks and forehead for hours.

That said, we couldn’t find good clinical trials that tested pillowcase-changing as an acne treatment. So a fresh pillowcase twice a week is a cheap, harmless habit, not a proven fix. If acne is persistent or leaving marks, see your doctor or pharmacist about treatment.

For eczema, the connection is more concrete in some people. Allergy UK lists itchy or worsening eczema among the symptoms linked to dust mite allergy. Not everyone with eczema is allergic to dust mites, though, and the evidence on whether mite-reduction measures actually improve eczema is mixed. That question gets its own article.

A simple routine that works for most homes

• Wash sheets and pillowcases weekly, in a fragrance-free detergent at the labelled dose.
• Use hot water (55 to 60 °C) for bedding if someone has a dust mite allergy; otherwise follow the care label.
• Wash or freeze pillows a few times a year, or cover them.
• Keep bedroom humidity in check. Health Canada suggests 35 to 50 percent, which means a dehumidifier in a damp basement bedroom and, often, a humidifier in a dry Canadian winter.
• Dry bedding fully before putting it back. Damp fabric is exactly what mites and moulds like.

If you’re picking a detergent for bedding that touches sensitive skin every night, you can browse fragrance-free laundry options the panel has reviewed.

The short version: weekly washing of sheets and pillowcases is a solid habit, hot water earns its place mainly when dust mites are the concern, and pillows deserve more attention than they get. Clean bedding is a small, reliable win for comfortable skin, even if it isn’t a cure for acne or eczema on its own.