Alopecia areata usually announces itself as a smooth, round bald patch that was not there a few weeks ago. There is no rash, no scale and usually no itch. The skin underneath looks completely normal.
The bald patch itself looks much the same on every skin tone, because the skin is not inflamed. On brown and Black skin the exposed scalp can look a little lighter or darker than the skin around it, and that evens out. The detail worth knowing on any skin tone is the pore openings: alopecia areata leaves tiny dots where the hairs were. A patch that is smooth and shiny with no visible openings is not alopecia areata and needs checking quickly.
Several kinds of hair loss look alike at a glance. See Lookalikes near the bottom of this page.
Alopecia areata is an autoimmune condition. Hair follicles normally sit in a spot the immune system leaves alone. In alopecia areata that protection breaks down, immune cells gather around the growing follicle, and the hair falls out. The follicle itself survives. It is switched off rather than destroyed, and that is the reason regrowth stays possible even after years of a patch being bald.
Genes do most of the setup. Around one in five people with alopecia areata has a close relative with it, and it travels with other autoimmune conditions — thyroid disease, vitiligo, type 1 diabetes, coeliac disease. Something then seems to tip it over: a viral illness, a stressful stretch, or nothing anyone can identify. Stress comes up often enough to take seriously as a trigger, but it is not the cause, and having it is not evidence that you handled something badly. Most people never find a trigger at all.
Nothing on a shelf switches off the immune attack behind alopecia areata. What is here either supports regrowth at the margins or helps you live with a patch while you decide what to do about it.
Worth going in early, because the treatments that work best work best on recent, active loss.
What the visit gets you: a firm diagnosis from a scope rather than a guess, blood tests for the conditions that travel with it, a steroid injection that can often be done the same day, and a straight answer about whether your disease is severe enough to justify a JAK inhibitor.
Alopecia areata is mostly recognised by looking, but several tests here genuinely change what happens next.
Allergy panels and hormone panels get offered here fairly often and rarely change anything.
This is where the real treatment sits. What you are offered depends on how much hair you have lost, how fast it is moving, and how long the patches have been bald.
Done in a clinic. For a small number of patches, the first option here is usually the first thing tried — and often the only thing needed.
The diagnosis is usually made the same day with a scope. If the patch is small and new, watching it for a few months is a reasonable plan.
Repeated every four to six weeks. When they work, regrowth usually shows at about eight to twelve weeks. Fine, pale hairs come first and thicken up over months.
These are slow. Meaningful regrowth typically takes three to six months, and the trials measured their best results at nine to twelve months. Blood tests are done before starting and repeated throughout.
New hair often arrives white or very fine. Colour and thickness usually return over six to twelve months, though a patch sometimes stays lighter than the rest.
Alopecia areata is unpredictable. Many people have one episode and never another. Others have it come and go for decades. A minority lose most or all of their hair. No test predicts which group you are in, and anyone who tells you otherwise is guessing.
Alopecia areata does not make you ill. It does not scar, it does not damage the scalp, and the follicles stay alive even after years of a patch being bald.
Several kinds of hair loss look similar at first glance, and they are treated very differently.