Keratosis Pilaris

Craig Kraffert, MD

Keratosis pilaris (KP) is a skin condition that commonly shows up as rough bumps around hair follicles on the back of and outer side of the upper arms. KP is a common and generally harmless condition that can be quite bothersome. Worldwide, approximate one in two people have KP, which is inherited in a dominant fashion. Only one copy of the KP gene is required for KP to develop. If one parent has KP, the chance of the couple’s child having KP is at least 50 percent. If both parents have the condition, the odds are even higher.

When, Where and Why Does Keratosis Pilaris Develop?

KP can present at any age on any area of the skin with hair follicles. The most common sites of involvement are the on backs of the arms, but it also often involves the front of the thighs and occasionally on the face, particularly in children. The bumps of KP on the faces of children and young adolescents can coexist or be confused with acne. KP is typically most developed and noticeable during adolescence. It slowly improves thereafter. In some people, KP is very widespread involving the body, arms, legs and face. Such widespread cases are particularly difficult to treat. KP is generally easy to diagnosis but misdiagnosis can occur in unusual cases.

What Causes Keratosis Pilaris?

The bumps of KP result from reduced shedding of excessively adherent outer skin scales around affected hair follicles. This results in formation of scaly bumps around affected follicles. This scale buildup often entraps the hair within the follicle. The trapped hair gets bunched up and may lead to a red irritated bump that may even fill with pus. These pus-filled red bumps are often confused with bacterial folliculitis or acne.

Treatment of Keratosis Pilaris

Treatment of KP is sometimes difficult and there is no universally effective treatment. Sun exposure temporarily helps KP but can cause cumulative damage to the skin over time, so it is not a recommended treatment. Moisturizing creams with lactic acid such as Amlactin or LacHydrin may be helpful. Urea containing products such as Ultramide 25 and high potency glycolic acid products such as Aqua Glycolic are also potentially beneficial. These products generally need to be applied at least twice daily for best results. They work by softening the adherent skin scales around the follicle enabling them to be shed more easily. Some people find that the use of a Buff-Puff or Clarisonic, either to apply the medicated creams or to abrade the skin during washing, may increase the benefits of these products. Other people find that this abrasion simply causes extra irritation and aggravates the KP. Vitamin A derivatives and analogs such as Retin A and Differin may also be helpful in some cases. The benefits of vitamin A derivatives in general and Retin A in particular are often limited by irritation.

KP does not necessarily require treatment. When treatment is desired, obtaining good results is challenging, even with guidance of an experienced dermatologist. Since KP is genetic, the skin returns to its pretreatment character if treatment is discontinued. The treatment of KP is best individualized and may require trials of several different products and application methods for optimal results. The good news is that virtually every case of KP can be improved if the patient is motivated and willing to apply ongoing treatment.