Other causes, however — such as cancer and certain types of head injury — are more serious.
In this article, learn about the various causes of bumps on the forehead, when to see a doctor, and some effective treatment options.
A pimple is a small pustule or papule on the skin.
These small bumps develop when the oil glands in the skin become blocked or infected.
Pimples can occur anywhere on the face, including the forehead. A person may develop a single pimple, or a number of pimples.
A small cluster of pimples typically does not require treatment. However, a more widespread outbreak, known as acne, can lead to scarring.
Some treatment options for acne include:
- benzoyl peroxide
- retinoid creams
- antibiotic ointments or creams
2. Skin cysts
A skin cyst is a harmless, fluid filled lump that develops beneath the skin. It is typically round or dome shaped, and it may be white or yellow.
Skin cysts can develop anywhere on the skin, including on the forehead.
Cysts are a collection of skin cells and keratin, which is a protein present in skin. Ordinarily, the keratin-producing skin cells travel to the surface of the skin, where they slough off.
Sometimes, however, the cells will move in the opposite direction, instead entering the deeper layers of the skin. Here, the trapped skin cells cluster together to form a cyst that contains keratin.
Cysts are usually slow growing. Some may grow to the size of a pea, whereas others might be several centimeters across.
Although cysts are generally painless, they may become painful if an infection develops. Try to avoid popping cysts, as this increases the risk of infection and scarring.
Holding a warm, clean washcloth against a cyst can reduce inflammation and encourage it to heal.
If a cyst becomes particularly bothersome, a doctor may recommend surgical removal. This usually results in scarring.
3. Insect bites and stings
Insect bites and stings can cause localized redness, pain, and inflammation. An insect bite on the forehead could result in a bump or swelling in that area.
Some people are allergic to insect bites and stings, and these allergies may be mild to severe.
For milder allergies, people can try applying a corticosteroid cream to alleviate localized skin irritation. Oral antihistamines can also help reduce allergy symptoms.
For more severe allergies, a person may require immediate treatment with epinephrine. Left untreated, severe allergies can result in a life threatening condition called anaphylaxis.
Certain insect bites and stings can cause particularly severe signs and symptoms, such as:
- high blood pressure
- rapid heartbeat
- jerky muscle movements
- nervous system toxicity
- organ failure
Some insects also transport bacteria or viruses, which can result in infection or disease.
A person should see a doctor immediately if they develop any symptoms of allergy, infection, or organ dysfunction following an insect bite or sting.
4. Scalp hematoma
A hematoma is a collection of blood that forms outside of a large blood vessel.
Scalp hematomas are those that develop beneath the skin of the scalp. They may create a visible bump on the head.
Scalp hematomas typically develop as a result of trauma to the head. Some common causes of head trauma include:
- vehicle accidents
- fights or assaults
- contact sports, such as boxing, football, and hockey
Scalp hematomas usually result from damage to skin and muscle rather than damage to the brain itself. However, they are often associated with more serious injuries within the skull.
Children and adolescents have a higher risk of developing a scalp hematoma in conjunction with a more serious head injury. For this reason, a child who experiences a head injury should receive immediate medical attention.
In some cases, a head injury can cause an internal bleed in the brain. A brain bleed increases pressure in the skull, and this can be fatal if a person does not receive prompt medical treatment.
A person should see a doctor if their scalp hematoma increases in size or is accompanied by symptoms other than pain at the site of trauma.
Most cases of head trauma are mild, so most people who go to the emergency room will be able to leave the same day.
However, certain people are at increased risk of developing a brain bleed following a head injury. The following people may therefore require hospitalization:
- people with bleeding disorders
- people who take anticoagulant, or blood thinning, medications
- people who take antiplatelet medications
- people who have undergone brain surgery
Treatment for a brain bleed involves surgery to reduce the bleeding and alleviate pressure within the skull.
Lipomas are soft, slow growing, benign tumors filled with fat cells. They may grow anywhere on the head, including the forehead.
Lipomas may also grow in the following areas:
Some researchers suggest that lipomas may develop on sites that have sustained previous injuries.
Other risk factors for the development of lipomas include:
Lipomas are harmless and generally do not cause any discomfort. However, a doctor may carry out tests to confirm that the tumor is a lipoma and not a liposarcoma. A liposarcoma is a type of cancerous tumor that can appear similar to a lipoma.
Doctors can treat lipomas with steroid injections or by surgically removing them.
An osteoma is a benign, bony growth. It may develop on top of another piece of bone, or on top of a different type of body tissue.
Osteomas typically develop on the skull, where they may appear as a bump beneath the skin. People with osteomas usually have only one bump, but on rare occasions, there may be multiple bumps.
People with osteomas may sometimes experience headaches and neurological dysfunctions. They may therefore choose to have the osteoma surgically removed. Others may choose to have the osteoma removed for aesthetic reasons.
Following surgery, a doctor may send a sample of the osteoma for further testing. This is a precautionary measure to confirm that the growth is not cancerous.
7. Skull metastases
This type of cancer can sometimes spread, or metastasize, to other areas of the body. On rare occasions, cancerous cells may spread from the liver to the skull.
In 2015, doctors presented a case report of a 40-year-old male who presented with a painless bump on his forehead. On further investigation, the doctors discovered that the bump was a cancerous growth that had metastasized from a hepatocellular carcinoma.
The doctors illustrated in their case report that hepatocellular cancer can progress without symptoms and spread to distant areas of the body.
In rare cases, a painless bump on the forehead may be a symptom of this type of cancer.
When to see a doctor
There are times when a bump on the forehead requires a visit to the doctor. The degree of urgency will depend on the suspected cause of the bump and a person’s symptoms.
Below, we explain when to see a doctor based on the suspected cause of the bump.
A child who experiences a scalp hematoma following a head injury should see a doctor as soon as possible.
Anyone who experiences these signs or symptoms following a head injury should seek emergency medical attention:
- loss of consciousness
- an inability to focus
- feeling “zoned out”
- vacant staring
- memory loss
- sleep disorders
- excessive drowsiness
- loss of balance
- impaired cognition
- delayed verbal and motor responses
- slurred speech
- visual disturbances
- rapid or exaggerated mood swings
These symptoms might not occur immediately after the trauma but may occur days to weeks later.
Insect bites and stings
A person who is severely allergic to insect bites and stings requires immediate treatment with epinephrine. Without treatment, a person may develop anaphylaxis. This can be fatal.
It is important that a person calls 911 immediately if they or someone around them is experiencing any of these signs or symptoms of anaphylaxis:
- nausea or vomiting
- abdominal pain
- hives or skin rashes
- skin swelling
- repetitive coughing
- tightness in the throat
- a hoarse voice
- difficulty breathing or swallowing
- weak pulse
- rapid heart rate
- a feeling of doom
- dizziness or fainting
A person should speak to their doctor if they are concerned about a bump on the forehead.
It is important to monitor bumps on the forehead closely.
Any bumps that get bigger or present with other symptoms may require medical attention.
If a person is concerned about a bump on the forehead and they do not know the cause, they should speak with their doctor.
A doctor can diagnose the cause and recommend treatment options.
A person may develop a bump on the forehead for many reasons. Some causes do not require treatment. Others are more serious and will require immediate medical attention.
If a person notices a bump on their forehead, they should monitor it closely. If the bump becomes larger, changes color, or becomes painful, they should make an appointment with their doctor.