Hair Health . Symptoms guide
Sudden Patchy Hair Loss (Possible Alopecia Areata)
Quick answer
Sudden, coin-shaped bald patches appearing within days or weeks are characteristic of alopecia areata, an autoimmune condition where the immune system attacks follicles. Alopecia areata is associated with other autoimmune conditions (especially thyroid), so a targeted panel checking for thyroid autoantibodies (TPO) and thyroid function is clinically justified alongside a formal dermatological evaluation.
This patient information is being clinically reviewed by our team. The factual content draws on UK guidance (NHS, NICE, British Association of Dermatologists, and other specialist society guidance where cited).
What this might be
- Alopecia areata. Autoimmune. Usually treatable; spontaneous regrowth is common.
- Associated thyroid autoimmunity. Hashimoto and Graves disease cluster with alopecia areata.
- Tinea capitis (scalp ringworm). Less common in adults but possible. Look for scaly, flaky or boggy patches with broken hair stubs rather than smooth bald spots, usually itchy. Requires a different treatment path.
Signs you need an expedited consultant dermatology referral
These features are not a 999 or NHS 111 emergency. They are signs that warrant prompt specialist input rather than waiting for standard blood panel results. Ask your GP for an urgent dermatology referral, or arrange a same-week appointment with a consultant dermatologist.
- Rapid spread beyond the original patch
- Loss involving eyebrows, eyelashes or beard
- Total scalp or body hair loss
Common features that suggest this
- Smooth, coin-shaped patch of hair loss
- Tingling or itching before the patch appeared
- No visible scarring
- Family history of autoimmune conditions
Recommended tests
Same-day appointments at our Harley Street clinic, results clinician-reviewed.
Need a marker not in these panels? Build a custom panel and a GMC-registered clinician will design one for you.
Markers your clinician will commonly look at
These are the individual blood markers in the recommended panels above. Click any to read what it measures, its UK reference range, and what high or low values mean.
Testing advice
No fasting. A dermatology referral is often appropriate; our panels complement that by checking for associated thyroid and nutritional contributors.
Common questions
Will my hair grow back?
In most early cases, yes, often within 6 to 12 months. Recurrent or extensive disease has a more variable course and benefits from specialist input.
Should I be tested for thyroid antibodies?
Yes, if alopecia areata is suspected it is worth checking. Alopecia areata often runs alongside autoimmune thyroid disease, so a quick blood test for thyroid antibodies can pick up a related condition early. Our <a href="/panels/advanced-hair-and-hormone-check/">Advanced Hair & Hormone Check</a> includes both <a href="/biomarkers/tpo-antibodies/">TPO antibodies</a> and <a href="/biomarkers/thyroglobulin-antibodies/">thyroglobulin antibodies</a>. The two work together: TPO is raised in around 95 percent of Hashimoto cases, and thyroglobulin in around 70 to 80 percent, so testing both gives the clearest picture.
Related symptoms
Sources and further reading
This page provides general information only and is not a substitute for medical advice. A GMC-registered clinician will review your results and tailor any recommendations to you personally.