Many types of bumps can appear on the skin. Papules, skin tags, and other bumps are often not serious, but some skin changes can be a sign of cancer.

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As a result, anyone who notices any changes to their skin should speak with a doctor to rule out severe conditions.

This article looks at the symptoms, diagnosis, and treatment of some common causes of bumps on the skin.

Papules and pustules

Doctors define a papule as any raised lesion or new growth on the skin that is less than 1 centimeter in diameter. Examples of papules and their causes include:

A pustule is a type of papule that contains fluid or pus and typically has discolored or inflamed skin around it. Some papules can develop into pustules, such as acne.

Both inflamed acne papules and pustules can appear when the pores of the skin become clogged with old skin cells, oil from the skin, and bacteria.

Other examples and causes of pustules include:

Treatment will depend on the cause and type of pustule.

Skin tags

Skin tags are another common type of growth on the skin. The medical name for a skin tag is acrochordon. Skin tags tend to be flesh-colored growths that hang from the surface of the skin by a “stalk.”

Skin tags become more common as people age, and they usually appear in areas where skin rubs on skin, such as in the armpits, the groin, and around the neck.

These growths do not usually cause pain, and they are almost always benign, so doctors consider them a cosmetic concern rather than a medical issue. However, in rare cases, some forms of skin cancer can resemble a skin tag.

Skin tags do not go away on their own. Anyone looking to remove them will need to contact a doctor.

Learn more about removing skin tags.

Angiomas and hemangiomas

Hemangiomas are a type of noncancerous growth that can appear on the skin. They are typically red or dark purple, depending on skin tone, and people sometimes call them birthmarks or “strawberry marks.” A baby may be born with this growth, or it may appear in the weeks following birth.

Angiomas are small, discolored papules that develop on the skin. They can appear at any age but become more common after a person turns 40. They may be less noticeable in people with skin of color.

These skin bumps do not require treatment unless they bleed or are painful, but some people may wish to remove them for cosmetic reasons.

A doctor may use electrocauterization, laser therapy, or liquid nitrogen to remove angiomas. More extensive surgery may be necessary to remove a hemangioma if it is damaging nearby tissue or organs.

Doctors can typically diagnose both conditions during an appointment, but they may monitor the growths for signs of other skin conditions, including skin cancer. If the skin bumps are not causing issues, doctors may choose to observe them rather than treat them.

Although there are many benign causes of skin bumps, this symptom might indicate cancer in some cases.

Actinic keratosis

Skin cancers and precancerous lesions usually result from excessive exposure to the sun or other sources of UV light. Precancerous growths include actinic keratoses.

Actinic keratosis often appears on areas of the body that get exposed to UV light. These areas include the:

  • face
  • scalp
  • ears
  • lips
  • shoulders
  • neck
  • chest
  • arms
  • legs
  • back
  • back of the hands

Actinic keratoses appear as rough, scaly patches that people often describe as “dry patches.” Occasionally, they are raised in texture. They can come and go and typically show up more when in the sun. They can sometimes be tender to the touch.

About 10% of actinic keratoses can turn into squamous cell carcinoma, although this percentage is higher among people with a weakened immune system.

Doctors can treat actinic keratoses in the office with liquid nitrogen. Other treatment options include topical chemotherapy creams, such as aminolevulinic acid HCl (Levulan), which doctors might use alongside blue light therapy.

Basal cell carcinoma

The most common type of skin cancer is basal cell carcinoma (BCC), with doctors diagnosing more than 3 million cases every year in the United States. BCC can look like an open sore, a papule or growth that does not heal or bleeds easily on its own, a shiny bump, or a discolored scaly patch.

BCC usually results from intense sun exposure and very rarely spreads to other areas of the body. However, it is important to get treatment for BCC to prevent it from destroying the surrounding skin and potentially invading nerve tissue.

Mohs surgery is the gold standard for removing BCC. A surgeon removes the visible tumor and a very small amount of the surrounding tissue.

Other treatment options include:

  • electrosurgery
  • excisional surgery
  • cryosurgery
  • topical medications
  • radiation therapy
  • photodynamic therapy

Squamous cell carcinoma

Squamous cell carcinoma is the second most common type of skin cancer. Squamous cells are present throughout the body, as they line the throat, skin, lungs, and organs.

Squamous cell carcinoma can develop anywhere these cells are present. It often presents as a rough, scaly patch, but it can also look like a wart, dark brown mole, or open sore.

Before the cancer develops, some people may notice signs of skin damage, such as age spots or patches of discolored skin. In some cases, actinic keratosis develops into squamous cell carcinoma.

This type of skin cancer is more common in people with fair skin, but People of Color can also develop it. When they do, the cancerous spots tend to be in areas that do not commonly have exposure to the sun, such as the mouth, genitals, or anus.

Squamous cell carcinoma is not usually life threatening, but the tumor can grow large enough to injure nerves and blood vessels.

A doctor will likely take a biopsy of the spot to determine whether it is a squamous cell carcinoma or another type of skin cancer or lesion.

The treatment options include surgical removal, liquid nitrogen, and radiation therapy.

Keratoacanthomas

Keratoacanthomas are dome-shaped tumors with a crater-like area in the middle that consists of a keratinous plug. They can grow quickly, measuring up to 1–3 centimeters.

There is some debate about the classification of these tumors. Some experts consider them to be benign. However, other experts consider them to be precancerous or a form of squamous cell carcinoma.

Many skin cancer experts suggest removing them with surgery as they can be challenging to distinguish from SCC and their growth can be unpredictable.

Melanoma

The most aggressive type of skin cancer is melanoma.

Melanoma can affect any area of the body. It can grow deep into the skin and may also affect the lymph nodes and blood vessels. Without treatment, melanoma can spread to the bones and organs.

Experts estimate that doctors will diagnose 197,700 new cases of melanoma in 2022 in the U.S. Of these, 97,920 will be noninvasive, and 99,780 will be invasive.

Despite only accounting for about 5% of all skin cancer diagnoses in the U.S., melanoma is responsible for the majority of deaths from skin cancer.

Melanomas are typically dark brown, pink, or black with an irregular border, although they can also be multicolored. They may sometimes arise from a large or atypical mole.

In rare cases, they appear as growths with no melanin, which is known as amelanotic melanoma. These are faint and can be difficult to detect, increasing the risk of the cancer spreading.

It is important to adopt sun-safety habits to protect the skin. People should avoid direct sunlight for prolonged periods, especially between the hours of 10 a.m. and 4 p.m.

The advice is to apply 1 ounce of sunscreen with an SPF of 15 or higher to the entire body 30 minutes before going outside. Those who plan on being outside for a long time should use a broad-spectrum sunscreen with an SPF of 30 or higher. They should reapply the sunscreen every 2 hours.

A sunscreen with a physical blocker, such as zinc oxide or titanium dioxide, might provide better protection. People with sensitive skin should look for noncomedogenic products.

It is also important to avoid using tanning beds, which increase the risk of skin cancer.

People should check their skin once a month and contact a doctor if they notice any new or changing lesions, or anything that itches, bleeds on its own, or does not heal.

People should examine their skin at home each month and let a doctor know if they notice any new or changing skin symptoms. It is important for the doctor to carry out a physical examination to rule out potentially severe conditions, such as skin cancer.

The doctor might also need to carry out tests to confirm a diagnosis. For example, carcinomas can often resemble other skin conditions, such as psoriasis or eczema, so a biopsy may be necessary.

Once the doctor has the results of the biopsy, they can decide on the most effective treatments.

There are many different types of bumps that appear on the skin. Examples include skin tags and a variety of papules and pustules, such as pimples, warts, moles, and eczema.

Some bumps on the skin may indicate types of skin cancer. People should examine their skin regularly and speak with a doctor if they notice any new or changing skin symptoms.