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Keratosis Pilaris (KP)

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Medical Author:

Nili N. Alai, MD, FAAD

Nili N. Alai, MD, FAAD

Dr. Alai is an actively practicing medical and surgical dermatologist in south Orange County, California. She has been a professor of dermatology and family medicine at the University of California, Irvine since 2000. She is U.S. board-certified in dermatology, a 10-year-certified fellow of the American Academy of Dermatology, and Fellow of the American Society of Mohs Surgery.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What is keratosis pilaris (KP)?

Keratosis pilaris (KP) is a very common skin disorder seen in many people of all ages. It is a benign condition that presents as numerous small, rough, red, or tan bumps primarily around hair follicles on the upper arms, legs, buttocks, and sometimes cheeks. KP creates a "goose bumps," "gooseflesh," or "chicken skin" appearance on the skin. A majority of people with KP may be unaware that the skin condition has a designated medical term or that it is treatable. In general, KP is often cosmetically displeasing but medically completely harmless. KP is frequently noted in otherwise healthy people.

Who gets keratosis pilaris?

Anyone can get KP. Although it is commonly a skin condition of children and adolescents, it is also seen in many adults. KP is estimated to affect between 50%-80% of all adolescents and approximately 40% of adults. Females may be more frequently affected than males. Age of onset is often within the first 10 years of life and can particularly get worse during puberty. However, KP may begin at any age. A large percentage of patients have other people in their family with the same condition. It has been commonly been seen in twins. KP is also seen in atopic dermatitis patients and patients with very dry skin.

What is the prognosis of patients with keratosis pilaris?

Overall, KP tends to be a chronic skin condition periodically becoming worse or better. KP is a benign, noncontagious, self-limited skin condition that tends to be mild. KP frequently improves with age in some patients. Many patients note improvement of their symptoms in the summer months and seasonal flares in colder winter months. More widespread, atypical cases of KP may be cosmetically distressing.

Will I eventually outgrow keratosis pilaris?

KP usually improves with increasing age. KP may even spontaneously clear completely after puberty. However, more frequently the condition is chronic with periodic exacerbations and improvements. Many adults still have the skin condition into their 40s and 50s.

Does keratosis pilaris affect the entire body?

Although possible, it is fairly rare to have KP all over the body. The lesions in keratosis pilaris most characteristically involve the back of the upper arms. Other common locations include the thighs and buttocks and occasionally the face. It does not affect the eyes, mouth, palms, or soles.

What does keratosis pilaris look like?

Typically, KP patients present with a scattered, patchy rash made of very small red or tan bumps. Often, 10-100 very small slightly rough bumps are scattered in an area. The affected area may have a fine, sandpaper-like texture. Some of the bumps may be slightly red or have an accompanying light-red halo indicating inflammation.

What does keratosis pilaris look like?

Sometimes, a small, coiled hair is trapped beneath the rough bump. Acne whiteheads, called milia, may also be in the same areas as KP. Patients may complain of a rough texture and an irregular cosmetic appearance of the skin. The cheeks may appear pink, red, flushed, and be studded with very small (pinpoint) bumps.

Keratosis pilaris may cause bumps on the backs of the upper arms, as seen here.