Whenever you encounter unfamiliar bumps on your skin, it can be stressful. You might ask yourself questions such as: “Are the bumps dangerous? Will they go away? What caused these bumps to begin with?”

Bumps on the arms are pretty common. Unless they gradually change or get larger over time, they are usually harmless.

Most bumps on the arms are caused by a condition called keratosis pilaris. There are other possible causes as well, ranging from inflammatory skin conditions to irritation, such as folliculitis.

Because of the wide range of possible causes, you shouldn’t self-diagnose bumps on your arms. However, you can use the information below to start investigating the underlying causes, which you can then discuss further with a dermatologist or doctor.

Keratosis pilaris, commonly known as chicken skin, is the most common cause of bumps on your arms.

This condition is characterized by small red or brown bumps that develop on the backs of your upper arms. They may also occur on the backs of your thighs and the buttocks.

While keratosis pilaris can be frustrating, it isn’t harmful.

Like acne, the bumps develop when dead skin cells get trapped in your pores. Some, but not all, of the bumps may have pimple-like heads. However, most keratosis pilaris bumps on the arms are small and flat.

What makes keratosis pilaris difficult to prevent entirely is the fact that it can be hereditary.

However, since the bumps are linked to the buildup of dead skin cells, you can help treat them and prevent others from forming with regular exfoliation. Dermabrasion and chemical peels from a dermatologist can also help in more severe cases.

Dry, less humid times of the year can contribute to the development of these bumps. Regular exfoliation can still help, along with keeping your skin hydrated with lotion. While the bumps may feel dry and rough to the touch, keratosis pilaris is not itchy most of the time.

Genetics aside, you may be at risk for keratosis pilaris bumps if you have one or more of the following:

Keratosis pilaris also occurs more often in females, as well as teens and young adults.

Keratosis pilaris is the most common cause of arm bumps, but it isn’t the only possible cause.

It isn’t usually itchy, but some other types of arm bumps can be. If the bumps on your arms are itchy, then consider the possible causes below.

Itchy causes

Some bumps on the arms can be itchy, in part because of inflammation and irritation in the skin. Possible causes of itchy bumps that may develop on the arms include:

  • Eczema. This inflammatory skin condition can cause a red itchy rash that may be raised in some areas.
  • Hives. These are red bumps that develop from an allergic reaction.
  • Folliculitis. In folliculitis, inflamed hair follicles cause multiple bumps on the skin.
  • Heat rash. Heat rash is caused by excessive heat and results in clogged sweat in your pores.
  • Psoriasis. Psoriasis is an inflammatory skin condition in which excessive skin cell growth leads to notable red to silvery skin patches.

Non-itchy causes

In addition to keratosis pilaris, another typically non-itchy cause of bumps on the arms is acne.

Pimples on the arms can develop when your pores get clogged with:

  • dead skin cells
  • bacteria
  • dirt
  • oil

Skin cancers may or may not cause itchiness. This cause of arm bumps is rare, but prompt diagnosis is important in preventing the tumors from spreading.

Knowing what keratosis pilaris looks like can help you determine whether your arm bumps are related to it or to another common condition.

A doctor can also diagnose the bumps on your arms with a physical exam. Since there are numerous possible causes of skin bumps, it’s important to get the correct diagnosis so you can properly treat them.

In some cases, you may be referred to a dermatologist for diagnosis and treatment. This is especially true if your primary care doctor suspects an inflammatory skin condition, such as eczema or psoriasis.

If the cause of your arm bumps isn’t quite clear, a dermatologist may conduct a biopsy. Especially useful in ruling out skin cancers, a biopsy involves scraping off a small amount of the skin bump and studying it under a microscope.

As mentioned above, keratosis pilaris is treatable with regular exfoliation as well as deeper exfoliating treatments, such as dermabrasion. In severe cases, a dermatologist may prescribe a retinol cream to help clear up the bumps.

Exfoliation

Exfoliating can help other causes of arm bumps, too. This process helps remove dead skin cells from the top layer of skin so they don’t get trapped in your pores.

To that end, exfoliation techniques may be helpful for acne, psoriasis, and dead skin cell buildup. You can use a washcloth or loofah alternative to gently exfoliate.

Be careful not to scrub. This can cause irritation and possibly even more bumps to form.

Medications

Other treatments for bumps on your arms depend on the underlying causes. Exfoliation can irritate eczema, folliculitis, and heat rash. Plus, this process won’t get rid of more serious bumps, such as skin cancers.

Inflammatory skin diseases may be treated with topical creams to help soothe the inflammation and prevent more bumps from occurring.

Over-the-counter (OTC) creams with oatmeal or hydrocortisone can help soothe itchy skin bumps and provide some relief. If your skin doesn’t improve, you may need a prescription ointment.

If a healthcare professional suspects that allergies are contributing to your skin bumps, you may need to take an antihistamine. Skin reactions to allergens can take some time to clear up, but treatment and prevention will help take care of the related skin bumps.

While it’s tempting to self-diagnose arm bumps, it’s always a good idea to reach out to a doctor for confirmation. You should also contact a doctor if the bumps worsen or change in shape or size.

If you don’t already have a dermatologist, the Healthline FindCare tool can help you locate a physician in your area. Make an appointment if you start to see any signs of infection.

Symptoms of a skin infection include:

  • increased inflammation
  • oozing
  • pus from the bumps

Bumps on the arms can be discomforting, but they’re an extremely common phenomenon. In most cases, keratosis pilaris (chicken skin) is to blame, and it can be cleared up with regular exfoliation.

Other causes of arm bumps may require a doctor’s visit and medical treatment. When in doubt, it’s always a good idea to reach out to your doctor.