One cause of bumps on the arms is a condition called keratosis pilaris. These bumps are harmless, hard, and may look like small pimples or goosebumps.

A person may not need treatment for keratosis pilaris unless they develop any bothersome symptoms, such as dryness or itchiness.

Keep reading for more information about health issues that commonly cause bumps on the arms.

Keratosis pilaris is a benign skin condition that causes small, hard bumps to appear on the skin. The bumps contain extra keratin, which is a protein in the hair, skin, and nails. A buildup of dead skin cells contributes to the issue.

In older children and adults, keratosis pilaris typically appears on the buttocks, thighs, and upper arms. In younger children, the bumps usually form on the cheeks, but they can appear on the arms and thighs, as well.

A person is most likely to notice the issue when the skin is dry, such as during winter months. The bumps may disappear during warmer or more humid seasons.

Keratosis pilaris bumps may form dry, rough patches, or they may resemble goosebumps, pimples, or a rash.

The bumps may be skin-colored, white, or red, and they can be itchy.

According to the American Academy of Dermatology (AAD), the condition often develops before a child turns 2 years old.

About 50–80% of adolescents and at least 40% of adults may have keratosis pilaris. However, these estimates are likely low, as people often do not report the issue to their doctors.

Some factors that increase the chances of developing keratosis pilaris include:

Also, it may be a side effect of vemurafenib, a medication that can treat melanoma.

Because keratosis pilaris is generally harmless and tends to resolve over time, treatment is usually unnecessary. However, if the bumps are bothersome, certain home care strategies may help.

The AAD recommend taking the following steps:

  1. Gently exfoliate the skin to remove dead skin cells.
  2. Apply a chemical exfoliator, also known as a keratolytic.
  3. Use an oil-free moisturizer liberally.

They also provide the following advice for managing keratosis pilaris:

  • Make sure not to scrub the skin harshly.
  • Use the keratolytic only as directed.
  • Apply the moisturizer after using the keratolytic, after bathing, and whenever the skin feels dry.

Doctors can recommend other ways to help relieve any itchiness and reduce the bumpiness of the skin.

To address the bumps, they may prescribe or recommend an over-the-counter ointment or cream that contains one of the following ingredients:

  • lactic acid
  • alpha hydroxy acid
  • salicylic acid
  • retinoids
  • glycolic acid
  • urea

These medications help get rid of dried skin cells. A doctor may also recommend creams or lotions to help with moisturizing the skin.

One study suggests that a combination of natural glycolic acid and salicylic acid may be the best way to restore the skin’s texture, as 70–80% of participants who used the combination saw smoother skin with less oiliness and a more even texture.

If other treatments fail, a doctor may recommend laser therapy to reduce the bumps and any discoloration.

A person with keratosis pilaris can take some steps to prevent bumps from forming. The AAD recommend:

  • using a thick, oil-free moisturizing cream
  • moisturizing immediately after bathing, while the skin is still damp
  • using moisturizer whenever the skin feels dry
  • considering hair removal techniques other than shaving or waxing, which can make keratosis pilaris worse
  • limiting showers and baths to once a day and keeping them short
  • avoiding bar soap in favor of a mild cleanser
  • using a humidifier if the skin is dry
  • avoiding self-tanners

There are many possible causes of bumps on the arms. For example:

  • Contact dermatitis causes a bumpy rash that can be itchy and otherwise uncomfortable.
  • Eczema can form red, itchy patches or small, liquid-filled bumps that eventually crust over.
  • Acne can cause whiteheads or blackheads.
  • Folliculitis is the infection of hair follicles, which can form tender, red, pus-filled bumps — typically on areas that are shaved or exposed to frequent irritation.
  • Heat rash often causes redness, itchiness, or tingling.

Only a healthcare provider can diagnose the cause of bumps on the arms.

They will ask about general health, family history, and any other symptoms, and they will also examine the affected skin.

For people with any of the following, it may be a good idea to contact a doctor:

  • itchiness
  • dryness that causes discomfort
  • a displeasing appearance of the skin
  • concerns about the underlying cause

It may be especially important to receive professional attention if home care techniques are not working.

Also, see a doctor if a rash and a fever are present, as these can be symptoms of a more serious infection.

In many cases, bumps on the arms result from keratosis pilaris, a benign condition that usually requires no treatment.

Certain home care techniques can help reduce the bumps and any associated symptoms.

If these methods are ineffective and the bumps are causing discomfort, a doctor can recommend professional treatments.