A true merino wool allergy is very unlikely: a 2017 review of the medical evidence, led by Australian dermatologists and allergists, concluded that wool fiber has not been shown to be a skin allergen. What many people call a wool allergy is usually irritation from coarse fibers, roughly 30 microns and thicker, that prickle the skin. Fine Merino wool is far thinner than that, which is why it is worn next to the skin and used in bedding. Down-Under Wool has supplied Australian Merino wool and sheepskin products since 1988, and this guide explains what the research says, why some wool itches, whether merino wool is hypoallergenic and what to do if your skin reacts.
Can you be allergic to merino wool?
It is possible to react to a wool garment, but a genuine allergy to the merino wool fiber itself has not been demonstrated. The review, "Debunking the Myth of Wool Allergy" by Zallmann et al. in Acta Dermato-Venereologica (2017), looked at decades of case reports and studies and found that the evidence "fails to support the notion that wool is an allergen." Most of the older case reports had flaws in how they tested people, and the one study that met most testing standards was negative.
That does not mean a wool sweater can never make your skin red or itchy. It means the cause is usually something other than an immune reaction to wool, most often the thickness of the fibers. (For the fiber itself, see what wool is made of.)
What does the research say about wool and skin?
The 2017 review looked at each of the things wool has been blamed for. Its findings, in plain terms:
| Suspected cause | What the review found |
|---|---|
| Wool fiber | No reliable evidence of an allergy (either immediate or delayed type) to the fiber itself |
| Lanolin (wool grease) | Modern scouring removes most lanolin, to less than 0.5%; contact allergy from modern wool garments is highly unlikely |
| Chromium and formaldehyde from processing | Highly unlikely in modern wool garments; formaldehyde allergy is "no longer a concern" |
| Dyes | Sensitization to the reactive dyes used on wool is very low |
| Coarse fibers | The real cause of irritation: fibers of about 30 to 32 microns and thicker |
| Superfine and ultrafine Merino | Do not trigger enough itch nerve fibers to cause itch, are well tolerated and may help eczema management |
The authors declared no conflicts of interest. It is a narrative review of earlier studies rather than a new trial, so its eczema findings are best read as promising rather than settled.
Why does wool feel itchy?
Wool feels itchy when its fibers are coarse. A thick fiber end is stiff, so instead of bending when it touches the skin it pokes the skin and sets off the nerves that signal prickle and itch. Fine fibers bend away instead. According to the review, irritation is linked to fibers of about 30 to 32 microns and thicker, whatever the fiber is; coarse synthetic fibers can prickle too.
Merino is the finest common sheep's wool. The Woolmark Company puts Merino wool generally under 22 microns, compared with about 50 to 100 microns for a human hair, and says fibers below about 19.5 microns are the ones prized for next-to-skin garments. Coarser wools from crossbred sheep, often used for rugs and outerwear, are the ones most likely to scratch. Our guide to types of wool explains the fineness grades.
Is merino wool hypoallergenic?
Merino wool is not a known allergen, so for most people it behaves like a hypoallergenic fiber, but "hypoallergenic" is a marketing word rather than a test result, so look at the evidence behind it. Two things support Merino:
- The research. The 2017 review found no evidence that wool is an allergen, and that superfine Merino is well tolerated.
- Certification. Following research funded by Australian Wool Innovation, the certification body Allergy Standards Limited (ASL) added a standard in 2020 for bedding that contains Merino wool, so Merino bedding can now earn its "asthma & allergy friendly" mark (Australian Wool Innovation). The mark is awarded to individual products that pass ASL's tests, so check the product itself for it.
For bedding specifically, see are wool pillows hypoallergenic?
Is merino wool good for eczema?
Superfine Merino may help some children with eczema, according to a small trial. In the DESSINE study (Su et al., British Journal of Dermatology, 2017), 39 children aged 4 weeks to 3 years with mild to moderate eczema (atopic dermatitis) wore superfine Merino clothing for six weeks and cotton for six weeks, in random order. The authors concluded that superfine Merino "may assist in the management of childhood AD." It was a small study, funded by the wool industry's research body (Australian Wool Innovation), and the reasons are not yet clear; the review suggests the drier, steadier microclimate next to the skin may play a part.
If you or your child has eczema, ask your doctor or dermatologist before changing what you wear or sleep on, and keep using the treatment they recommend.
Merino wool allergy symptoms: what to look for
A reaction to a wool garment usually shows up as itching, prickling or redness where the fabric touches the skin, and it eases when you take the garment off. That pattern fits irritation from fibers, a detergent residue or a finish, rather than an allergy to wool.
- Note what you were wearing or lying on, how coarse it was and how it was washed.
- Try the same item after a wash in a gentle wool wash, or try a finer Merino item.
- If a rash keeps coming back, ask a doctor or dermatologist. A patch test can show what you are actually reacting to, which may be a dye, a detergent or something else entirely.
- Get medical help straight away for hives, swelling of the face or lips, or any trouble breathing, whatever you think the cause is.
Is a sheepskin allergy the same as a wool allergy?
Not quite. A sheepskin is a tanned hide with the wool still attached, so besides the wool fibers it has a leather backing and the chemicals used to tan it. A wool pad or blanket is shorn fiber only. If you think you react to sheepskin, our guide to sheepskin vs wool and allergic reactions to sheepskin explains the differences, and what sheepskin is covers how it is made. People who prefer to avoid leather can use a pure Merino wool pad instead, such as the Hospital Wool Fleece Bed Pad, made from 100% pure new Merino wool.
Choosing merino wool for sensitive skin
- Choose fine Merino. If a label gives the micron, lower is softer; next-to-skin Merino is generally under about 19.5 microns.
- Start small. A pillow cover or a pair of socks is an easy way to see how your skin feels. Our Merino wool pillow cover (M129D) slides over a standard pillow and is machine washable.
- Wash with a gentle wool wash. We use Woolskin on all our wool and sheepskin products. Rinse well so no detergent is left in the fibers.
- Keep it dry and aired. Wool absorbs moisture vapor, but a shake and an airing between washes keeps the pile fresh.
Our Merino wool bedding range includes fitted fleeces such as the Hospital Bed Nursing Fleece, pads and pillow covers, and the health benefits of merino wool pads are covered in a separate guide; read is it good to sleep on wool? for how wool bedding feels night to night.
Merino wool allergy FAQs
Can you be allergic to wool but not merino wool?
Yes, in the sense that many people who find ordinary wool itchy are comfortable in fine Merino. Their problem was coarse fibers, not an allergy, so a finer wool solves it.
Does merino wool itch?
Fine merino wool usually does not itch. Itch comes from fibers of roughly 30 microns and thicker, and next-to-skin Merino is much finer than that.
Is merino wool good for sensitive skin?
Fine merino is generally well tolerated by sensitive skin, according to the 2017 review. Start with one item and wash it in a gentle wool wash first.
Can lanolin in merino wool cause an allergy?
It is highly unlikely from modern wool clothing or bedding. Scouring removes most lanolin, leaving less than 0.5%, and the review judged lanolin contact allergy from modern wool garments to be very unlikely. People with a known lanolin allergy from creams should still check with their doctor.
Is merino wool asthma and allergy friendly?
Merino bedding can be certified "asthma & allergy friendly" under a standard Allergy Standards Limited introduced in 2020. Certification applies to individual products that pass testing, so look for the mark on the product.
Can babies wear merino wool?
Babies can wear superfine Merino clothing, and the DESSINE trial studied infants from 4 weeks old. For sleep, babies should sleep on their back on a firm, flat surface with nothing soft in the crib, as the NIH Safe to Sleep campaign advises.
Is wool hypoallergenic for pillows?
Wool pillow fillings and covers are not a known allergen; read the benefits of wool pillows for more.
The short version
A merino wool allergy is very rare, if it exists at all: the evidence does not show wool fiber to be an allergen, and modern wool carries very little lanolin, chromium or formaldehyde. Itch comes from coarse fibers of about 30 microns and thicker, and fine Merino is much finer. Merino is well tolerated by most sensitive skin and may even help some children with eczema, but see a doctor for any rash that keeps coming back. Questions about which of our wool products suits you? Contact us; we have been helping customers choose since 1988.
