Poliosis is a condition characterized by a distinct patch of white or gray hair, contrasting with surrounding pigmented hair. This occurs due to a localized reduction or absence of melanin, the pigment responsible for hair color, in affected hair follicles. While often a cosmetic concern, poliosis can appear on any hair-bearing area, including the scalp, eyebrows, and eyelashes.
What is Poliosis?
Poliosis is the presence of a depigmented, or white, patch of hair. It results from a lack of melanin in affected hair follicles, causing hair to appear white or discolored. It can manifest as a single or multiple patches, often seen on the scalp as a “white forelock.”
This condition can affect individuals of all ages, appearing at birth (congenital) or developing later (acquired). While poliosis itself is typically harmless and does not cause hair loss, its appearance can sometimes signal an underlying health issue. The absence of pigment is specific to the hair follicle, meaning the surrounding skin may or may not also be depigmented.
Causes of Poliosis
Poliosis can stem from various factors, broadly categorized into genetic predispositions or acquired conditions. The absence of melanin in the affected hair follicles is consistently linked to a decrease or lack of melanocytes, the cells responsible for melanin production.
Genetic factors often lead to congenital poliosis as a feature of specific inherited syndromes. Examples include Waardenburg syndrome, which can involve hearing loss and pigmentary changes, and piebaldism, characterized by congenital absence of melanocytes in certain areas of the skin and hair. Tuberous sclerosis complex, a genetic condition causing benign tumors in multiple organs, and neurofibromatosis type 1, a disorder affecting nerve tissue, can also be associated with poliosis.
Acquired poliosis develops later in life due to external factors or medical conditions. These can include inflammatory or autoimmune disorders, specific medications, or even trauma to the hair follicles. In some instances, the precise cause remains undetermined, leading to a classification of idiopathic poliosis.
Associated Conditions and Systemic Health
While poliosis itself is generally benign, its presence can sometimes be a visible indicator of a more significant underlying medical condition. This is why a medical evaluation is important, especially when poliosis develops suddenly. The depigmentation can be a symptom of systemic issues affecting pigmentation or other bodily systems.
Autoimmune diseases are frequently linked to acquired poliosis. Vitiligo, an autoimmune disorder causing depigmented skin patches due to melanocyte destruction, is often accompanied by poliosis, particularly in segmental cases. Vogt-Koyanagi-Harada (VKH) disease, a systemic autoimmune disorder affecting melanin-containing tissues in the eyes, ears, and central nervous system, can also manifest with poliosis, often involving the eyebrows and eyelashes. Alopecia areata, an autoimmune condition causing patchy hair loss, may also involve poliosis during hair regrowth or as pigmented hair selectively falls out.
Poliosis can also be associated with neurological conditions such as tuberous sclerosis and neurofibromatosis type 1, where it may appear over specific lesions. Thyroid dysfunction has also been observed in individuals with poliosis. Certain medications, including some used in chemotherapy (e.g., cetuximab) or for conditions like glaucoma (topical prostaglandin analogs), can rarely induce poliosis as a side effect. Inflammatory conditions have also been noted in association with poliosis.
Diagnosis and Management
Diagnosing poliosis typically begins with a visual examination by a healthcare professional. A comprehensive medical history is taken, including questions about family history and the onset of poliosis. A physical examination is also conducted to look for any other symptoms or signs of associated conditions.
Further diagnostic tests may be performed to identify or rule out any underlying medical conditions. These can include blood tests for autoimmune markers or thyroid function, a skin biopsy to examine hair follicles, or a Wood’s lamp examination to assess skin pigmentation. Imaging studies may also be considered if a neurological association is suspected.
Poliosis itself usually does not require medical treatment if it is solely a cosmetic concern. For those who prefer to conceal the white patch, cosmetic options such as hair dyes are available. If an underlying medical condition is identified, management focuses on treating that specific condition. Successful treatment of the underlying cause may or may not lead to repigmentation of the hair. Consulting a doctor is important for proper diagnosis and guidance regarding management strategies.