(from Lubbock Avalanche-Journal) When a reader posed a question to Dr Roach about their eyebrows that were disappearing from the outer edges he replies that a low thyroid is the first thing most doctors think of.
The caution is that even though the TSH level test is a reasonable screening test to take, it is a good idea to follow through with additional tests such as a thyroxine (T4), free T4 and T3.
There are also other causes of eyebrow loss that should be considered including autoimmune disease, inflammatory skin conditions and infection.
External reasons might also be considered too such as repeated plucking which has affected the follicles or the use of a new type of makeup which may have resulting in some kind of allergic reaction.
We have also added our thoughts and observations on thinning eyebrows as a result of thyroid problems.