Symptoms and causes


Keratosis pilaris can occur at any age, but it's more common in young children. Signs and symptoms include:

  • Painless tiny bumps, typically on the upper arms, thighs, cheeks or buttocks
  • Dry, rough skin in the areas with bumps
  • Worsening when seasonal changes cause low humidity and skin tends to be drier
  • Sandpaper-like bumps resembling goose flesh

When to see a doctor

Treatment for keratosis pilaris usually isn't necessary. But if you're concerned about the appearance of your or your child's skin, consult your family doctor or a specialist in skin diseases (dermatologist). He or she can often make a diagnosis by examining the skin and the characteristic scaly bumps.


Keratosis pilaris results from the buildup of keratin — a hard protein that protects skin from harmful substances and infection. The keratin forms a scaly plug that blocks the opening of the hair follicle. Usually many plugs form, causing patches of rough, bumpy skin.

No one knows exactly why keratin builds up. But it may occur in association with genetic diseases or with other skin conditions, such as atopic dermatitis. Dry skin tends to worsen this condition.