A natural white streak that occurs in the hair is known as poliosis, and if it was present at birth, chances are it is nothing to worry about; however, if it was acquired later in life, it could be the symptom of an underlying medical condition. Most cases of poliosis are found on the scalp, but the white streaks or patches of hair can be found on any part of the body.
Poliosis found later in life is acquired and is sometimes a side effect of a medical condition, such as Waardeburg's syndrome, tuberous sclerosis, thyroid disease, skin cancer and a variety of other genetic or autoimmune diseases and disorders.
There are instances where poliosis occurs after taking a specific medication or even after a bad fungal infection. Herpes zoster, otherwise known as shingles, can cause the white patch in the hair either temporary or permanently. Patients who have undergone radiation or chemotherapy often develop the white patching hair due to the treatment destroying pigment producing cells.
Anyone who develops poliosis is recommended to see a doctor right away. The doctor will run tests and conduct a medical history to find out if there is cause for concern. There is no cure for poliosis, but if there is an underlying medical problem at the root of the disorder it should be treated by a professional.