Poliosis

Poliosis refers to an patch of white hair. It is due to lack of melanin (pigment) in the hair shafts of the affected area. It is most often seen in scalp hair, but may also affect eyebrows, eyelashes or other sites.

Poliosis may occur because of an inherited defect in melanisation, or because of an autoimmune destruction of the pigment cells at the base of the hair, or because the hair follicles are damaged. The following conditions are sometimes associated with poliosis:

• Vitiligo
• Alopecia areata
• Halo moles
• Piebaldism
• Tuberous sclerosis
• Vogt-Koyanagi-Harada disease
• Waardenburg syndrome
• Allezandrini syndrome

It may also follow an injury or event such as herpes zoster (shingles) or radiotherapy.

Piebaldism

Alopecia areata

Vitiligo

Halo naevus

Vitiligo