Autoimmune disease and changes to your hair

The pattern matters. Smooth, clearly defined patches can occur when the immune system targets hair follicles, while widespread shedding may follow an illness flare, reduced food intake, iron deficiency, thyroid disturbance, or a medicine change. Hair loss by itself does not establish an autoimmune diagnosis.

Alopecia areata is an autoimmune condition that often presents with round or oval areas of hair loss and skin that may look otherwise normal. Some inflammatory autoimmune disorders can cause a sore, scaly, or scarred scalp, which needs earlier assessment because damaged follicles may not regrow normally.

People with Crohn's disease may experience diffuse shedding when active bowel inflammation, poor absorption, restricted eating, or blood loss reduces nutrients needed for hair growth. Abdominal symptoms and hair changes should be considered together, but neither confirms the cause without an examination and appropriate tests.

Photograph the same scalp areas in similar lighting and note when shedding began, whether it is patchy or widespread, and whether there is itching, scaling, pain, or broken hair. Record recent illness flares, weight or appetite changes, menstrual changes, and new or adjusted medicines.

Use gentle hair care while the cause is assessed: avoid tight styles, harsh chemical treatments, and high heat on fragile hair. Do not stop prescribed immune treatment or start high-dose supplements without clinical advice; both the underlying disease and unnecessary supplements can complicate care.

Book a medical appointment for rapid or persistent shedding, new bald patches, eyebrow or eyelash loss, or scalp redness, tenderness, crusting, or scarring. Also arrange review when hair changes accompany ongoing diarrhoea, abdominal pain, marked tiredness, joint swelling, or unexplained weight change.

Seek prompt help if a new medicine is followed by facial or tongue swelling, breathing difficulty, a widespread blistering rash, or faintness. These warning signs require urgent assessment regardless of the hair concern.

Ask whether the pattern suggests follicle inflammation, diffuse shedding, breakage, or another cause. Useful discussion points include whether blood tests for anaemia, iron stores, thyroid function, or selected nutrients fit your history; whether a medicine could contribute; and whether a dermatologist or gastroenterology review is appropriate.