Keratosis Pilaris (KP)

  • Medical Author:
    Gary W. Cole, MD, FAAD

    Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    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.

View the Adult Skin Problems Slideshow Pictures

What causes keratosis pilaris?

The exact cause of keratosis pilaris is unknown. There seems to be a problem with overproduction of the keratin part of the skin called hyperkeratinization. Keratosis pilaris is thought to be partly inherited (genetic) in origin. A majority of patients with keratosis pilaris have a known genetic predisposition and a high rate of affected family members. Many individuals have a strong family history of keratosis pilaris or "chicken skin." Keratosis pilaris can be present with ichthyosis vulgaris, dry skin seasonal inhalant allergies, rhinitis, asthma, eczema, and atopic dermatitis.

The bumps in keratosis pilaris seem to arise from the excessive accumulation of keratin (very small, dry skin particles) at the opening of individual hair follicles. The skin as examined under the microscope demonstrates mild thickening, and plugging of the hair follicle. The upper skin layers may have some dilation of the small superficial blood vessels, thereby giving the skin a red or flushed appearance.

How is keratosis pilaris diagnosed?

The diagnosis of keratosis pilaris is very straightforward and based on a typical skin appearance in areas like the upper arms. A family history of keratosis pilaris is also very helpful since there is a strong genetic component to the condition. The diagnosis is confirmed by the physician's clinical exam.

What else could it be?

Other medical conditions can mimic keratosis pilaris. Keratosis pilaris may resemble acne, milia, folliculitis, eczema, atopic dermatitis, facial rosacea, or dry skin (xerosis). Keratosis pilaris may also resemble uncommon skin conditions like lichen spinulosus, pityriasis rubra pilaris, phrynoderma (vitamin A deficiency), ulerythema ophryogenes, ichthyosis vulgaris, eruptive vellus hair cysts, keratosis follicularis (Darier disease), Kyrle disease, lichen nitidus, lichen spinulosus, perforating folliculitis, and trichostasis spinulosa.

In India and other countries, a specific condition called erythromelanosis follicularis faciei et colli occurs. This unusual condition has a possible genetic relationship to keratosis pilaris. Erythromelanosis follicularis faciei et colli is characterized by the triad of hyperpigmentation (darker skin color), follicular plugging (blocked hair follicles), and redness of the face and neck.

Are there any lab tests to help diagnose keratosis pilaris?

Since the appearance of keratosis pilaris is easily recognized, specific laboratory tests are not needed for the diagnosis. Skin biopsy (surgically taking a small piece of skin using local numbing medicine) may be useful in atypical or widespread cases.

What does keratosis pilaris look like under the microscope?

Microscopic examination of the body tissue by a pathologist or dermatopathologist under high magnification is called histopathology or pathology. Histopathology of keratosis pilaris shows mild hyperkeratosis of the epidermis (thickening of the outer layer of skin), hypergranulosis (increase in the special granular cells of the epidermis), and plugging of individual hair follicles. The upper dermis (layer of the skin below the epidermis) may have some microscopic inflammation called mild superficial perivascular lymphocytic inflammatory changes.

Medically Reviewed by a Doctor on 2/23/2015
VIEW PATIENT COMMENTS
  • Keratosis Pilaris - Cause

    What was the cause of your keratosis pilaris?

    Post View 15 Comments
  • Keratosis Pilaris - Experience

    Please describe your experience with keratosis pilaris (KP).

    Post View 4 Comments
  • Keratosis Pilaris - Treatment

    What was the treatment for your keratosis pilaris?

    Post View 6 Comments
  • Keratosis Pilaris - Affected Areas

    Where on your body do you have keratosis pilaris? Have you found an effective treatment?

    Post View 5 Comments

Health Solutions From Our Sponsors