Every so often we encounter someone who tells us they love our blankets, but they can't have one because they're allergic to wool...
But, it's unlikely that you are actually allergic to wool. It's hard to tell someone this in person, so we thought we'd go looking at the evidence.
Wool As a Skin Allergen
In a research article from 2017 published in Medical Journals Limited, nine authors examined articles from the last 100 years in Medline and Google Scholar (1). The researchers looked for evidence that wool causes cutaneous reactions, both immune-mediated (atopic dermatitis exacerbation, contact urticaria, allergic contact dermatitis) and non-immune-mediated (irritant contact dermatitis, itch).
Current evidence does not suggest that wool is a skin allergen.
Time to celebrate!
So What Makes Me Itchy?
"Prickle", the sensation to itch when your skin is in contact with specific fibers, is primarily caused by individual sensitivity, and the diameter of the fiber, measured in microns. Merino wool, which is the finest wool available, is typically 18-24 microns. Once the average diameter of fiber in a fabric exceeds 22 microns, one may begin to experience prickle, depending on your sensitivity. 100% Merino wool shirts can range from 16.1 to 17.5 microns. The finer the micron, the more expensive the wool.
For a look at the measurement of other natural fibers, check out this blog post.
(1) Zallman, Michaela, et al. “Debunking the Myth of Wool Allergy: Reviewing the Evidence for Immune and Non-immune Cutaneous Reactions.” Acta Dermato-Venereologica, Vol 97, Nov. 2017, https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-2655