Reversible causes of hair loss worth ruling out

Pattern hair loss is the most common reason for thinning, but it is not the only one. Some causes of hair loss are reversible, and treating the cause is more useful than starting a hair-loss prescription that will not address it.

This is why a good hair-loss assessment spends time on your history and, where it is warranted, a few blood tests, rather than going straight to a prescription.

Telogen effluvium: stress and shock shedding

Telogen effluvium is a temporary increase in shedding that follows a trigger, usually two to three months after the event. The triggers are common: a serious illness or high fever, surgery, childbirth, a crash diet or large rapid weight loss, severe stress, or starting or stopping certain medications.

It shows as a general thinning all over rather than a receding hairline, often with more hair than usual coming out when you wash or brush. The reassuring part is that it normally recovers on its own within six to nine months once the trigger has passed. The job of the assessment is to recognise it for what it is and avoid mistaking it for something permanent.

Iron deficiency

Low iron stores can cause or worsen hair shedding, and this is more common in women, particularly with heavy periods. The relevant blood test is ferritin, which measures your iron stores rather than the iron circulating at that moment.

Where ferritin is low, correcting it can reduce shedding and helps any pattern-hair-loss treatment work better. Iron should be replaced because a test shows it is low, not taken speculatively, because too much iron is its own problem.

Thyroid problems

Both an underactive and an overactive thyroid can cause hair to thin, usually alongside other clues such as changes in weight, energy, mood, temperature tolerance or periods. A simple thyroid function blood test settles the question, and treating the thyroid disorder is what helps the hair.

Vitamin D and nutrition

Low vitamin D is associated with hair shedding and is easy to check and correct. Beyond that, very restrictive diets and rapid weight loss can deprive follicles of the protein and micronutrients they need. For most people eating a reasonable diet, however, supplements add little, and we recommend them where there is a deficiency to correct rather than by default.

Alopecia areata and scarring conditions

Alopecia areata is an autoimmune condition that causes well-defined round or oval bald patches, sometimes appearing quickly. It is different from pattern hair loss and is managed differently.

Scarring alopecias, where the follicle is permanently destroyed and replaced by smooth scar tissue, often with redness, itch or scalp pain, are important to catch early because the window to preserve hair is short. Any patchy loss, scalp inflammation or scarring is a reason to be assessed properly rather than to start a standard hair-loss treatment.

Medications and other triggers

Some medications list hair shedding among their effects, including certain treatments for blood pressure, mood, acne and hormonal conditions. Tight hairstyles worn over long periods can also cause a specific traction loss at the hairline. Part of the assessment is simply going through what you take and what you do, because the answer is sometimes there.

What about biotin and hair vitamins

Biotin and the various hair-and-nail supplements are popular, and it is worth being clear about what they do. Genuine biotin deficiency is rare, and where it does not exist, taking more makes no difference to your hair. The wider point holds for most supplements: they help when they are correcting a deficiency that a blood test has shown, and add little otherwise.

There is also a practical catch. High-dose biotin can interfere with some laboratory blood tests, including thyroid and certain heart tests, and produce misleading results. If you take it, mention it before any blood test, because stopping it for a few days first may be needed for an accurate reading.

The honest summary

Most thinning turns out to be pattern hair loss, but the reversible causes are worth ruling out first, because treating them is often quicker and more complete than any hair-loss prescription. A short assessment with one of our doctors covers your history and arranges the few blood tests that are actually useful, so you start from the right diagnosis.

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If you want to move from reading to acting, the next step is a short, confidential assessment with one of our doctors.

Begin your assessment at this link. Online or in person at Westfield London.