Where have my eyebrows gone?
Madrosis is the term used to describe loss of eyebrow and eyelash hair & comes from the Greek word “Mados” which means to fall off. There are a number of different conditions implicated in the pathogenesis of madrosis, with thyroid dysfunction, my favourite topic, being a primary driver.
How is the thyroid involved?
One of the key signs seen in hypothyroidism is the loss of the outer third of the eyebrows; this is known as ‘hertoghes’ sign. At their correct levels, the thyroid hormones T3 & T4 function to reduce the death of hair follicles; T4 also extends the duration of the ‘anagen’ (growth phase) of the hair. Not enoughT4 & T3 leads to not enough hair growth, as well as more hair death!
The ratio of the telogen phase (resting phase of hair growth) to anlagen phase is increased in both hypo and hyperthyroidism leading to issues with hair growth (i.e. help I’m losing handfuls of hair or why is my eyelash & eyebrow hair now growing?).
Eyelash and eyebrow hair grow at a rate of 0.15mm per day and last approx 5-6 months. Because of this, if we’re working on growing these back, know it is not going to happen overnight! Silica and B vitamins will help with strengthening hair, but they key for reducing thyroid induced madrosis is to normalise thyroid hormone status.
Now, the truth is, that sometimes (often!) there are other things that also contribute to madrosis, for example when the hair loss is due to an autoimmune aetiology, e.g. if you have hashimotos.
Yep, as well as attacking parts of your thyroid, those pesky auto-antibodies can attack your hair follicles too! Lymphocytic infiltration (these are white blood cells that present as a marker of immune cell activity), have been found to surround the hair follicles in the anlagen phase invading the outer root sheath, preventing them from growing. So, don’t just rely on getting your TSH tested, make sure you get your T3 and thyroid antibodies tested too.
If you do have high thyroid antibodies and loss of eyebrow hair, focus on modulating the immune system. Different things have been found to work for different people but things to try include a gluten free diet, sunshine (due to the immune modulating action of vitamin D, hormone balancing, more sleep, stress reduction & nutrients such as inositol and selenium.
