Causes of Hard Scalp Bumps
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Finding a hard scalp bump may be concerning, but in most cases, it’s not serious. Some causes could be a skin condition, injury, infection, or abnormal cell growth.
Hallmarks of hard bumps on the scalp
You may notice a new bump on your scalp while combing, brushing, or washing your hair — which can be alarming. However, most causes of hard scalp bumps are treated easily, some may require medication and/or evaluation by a medical professional.
Common characteristics of hard scalp bumps
Depending on the cause, hard scalp bumps may present with the following.
- Large or small
- Soft or firm
- Single or multiple
- Mobile: This means it moves when you touch or press it.
- Fixed: This means it feels stuck in its location.
- Tender or not tender
- Itchy or not itchy
Common accompanying symptoms of hard scalp bumps
Scalp bumps can also present with the following.
Duration of symptoms
The length of time that you may experience a hard scalp bump can vary. When monitoring your scalp bump, keep track of its size, color, and any associated symptoms.
- Temporary: A scalp bump may last for only a few days before it resolves on its own.
- Persistent: A scalp bump may seem to grow over time or not go away.
Are painful scalp bumps serious?
Hard scalp bumps can be harmless or require treatment.
- Not serious: A small scalp bump that resolves on its own is not serious.
- Moderately serious: See a physician if you have a large scalp bump associated with redness or pain, especially if you also have a fever.
- Serious: See a physician for scalp bumps that grow and feel fixed in place.
What causes hard bumps on the scalp?
There are many potential causes for hard scalp bumps. The following details may help you better understand your symptoms and if and when you need to see a physician.
Skin infections or those within the body due to bacteria, viruses, or fungi can cause a hard scalp bump.
- Bacterial skin infections: Your scalp is covered in hair follicles, tiny sacs from which each strand of hair grows. Bacteria can infect hair follicles and lead to folliculitis. An open cut, if exposed, can lead to cellulitis, an infection of the skin and area under the skin. If your skin infection doesn't resolve, this can lead to an abscess or a pocket of pus as your body tries to fight the infection.
- Viral skin infections: Viruses can also cause small scalp bumps in the form of skin-colored warts.
- Fungal skin infections: Fungi can cause a variety of scalp infections, including ringworm, which causes an itchy, red, circular rash.
- Lymph node enlargement: Lymph nodes are small glands where the cells that fight infections live. Lymph nodes can grow in size and appear as single or multiple bumps in your scalp as they respond to an infection due to bacteria, fungi, or viruses.
Scalp bumps may be due to an injury to your scalp. Bumping your head may result in swelling or a “knot” to form. This knot is due to blood or fluid collecting under the skin of your scalp and can involve bruising and tenderness.
Abnormal cell growth
Sometimes a scalp bump can be due to abnormal growth of a variety of different cells that make up your body. These cells can include the following.
- Fat cells: These cells can grow into bumps called lipomas.
- Pigment-containing cells: Melanocytes can form into a melanoma.
- Basal cells: These skin stem cells can morph into basal cell carcinoma.
- Keratin collections: Scalp bumps can also be due to a collection of keratin, the main protein in your skin, and lead to cysts.
This list does not constitute medical advice and may not accurately represent what you have.
A cyst is a small sac or lump, filled with fluid, air, fat, or other material, that begins to grow somewhere in the body for no apparent reason. A skin cyst is one that forms just beneath the skin.
It's believed that skin cysts form around trapped keratin cells – the cells that form the relatively tough outer layer of the skin.
These cysts are not contagious.
Anyone can get a skin cyst, but they are most common in those who are over age 18, have acne, or have injured the skin.
Symptoms include the appearance of a small, rounded lump under the skin. Cysts are normally painless unless infected, when they will be reddened and sore and contain pus.
Diagnosis is made through physical examination. A small cyst can be left alone, though if it is unsightly or large enough to interfere with movement it can be removed in a simple procedure done in a doctor's office. An infected cyst must be treated so that the infection does not spread.
Top Symptoms: skin-colored armpit bump, marble sized armpit lump, small armpit lump
Symptoms that always occur with skin cyst: skin-colored armpit bump
Urgency: Wait and watch
Warts, also called common warts or verrucae, are small, rough, rounded growths on the top layer of the skin. They may appear alone or in clusters. Common warts are caused by the human papillomavirus (HPV) and are contagious through direct contact. They may spread from one place on the body to another simply through touch.
Lipoma is a word that translates as "fatty tumor," but a lipoma is not cancer. It is simply a growth of fat between the muscle layer and the skin above it.
The exact cause is not known. The condition does run in families and is associated with other unusual syndromes such as adiposis dolorosa, which is similar. Lipomas most often appear after age 40.
Symptoms include a soft, easily moveable lump beneath the skin, about two inches across. A lipoma is painless unless its growth is irritating the nerves around it. They are most often found on the back, neck, and abdomen, and sometimes the arms and upper legs.
It is a good idea to have any new or unusual growth checked by a medical provider, just to make certain it is benign.
Diagnosis is made through physical examination, biopsy, and imaging such as ultrasound or CT scan.
Most of the time, treatment is not necessary unless the lipoma is unsightly or is interfering with other structures. It can be removed through surgery or liposuction.
Top Symptoms: skin-colored groin bump, marble sized groin lump, small groin lump
Symptoms that always occur with lipoma: skin-colored groin bump
Urgency: Wait and watch
A skin abscess is a large pocket of pus that has formed just beneath the skin. It is caused by bacteria getting under the skin, usually through a small cut or scratch, and beginning to multiply. The body fights the invasion with white blood cells, which kill some of the infected tissue but form pus within the cavity that remains.
Symptoms include a large, red, swollen, painful lump of pus anywhere on the body beneath the skin. There may be fever, chills, and body aches from the infection.
If not treated, there is the risk of an abscess enlarging, spreading, and causing serious illness.
Diagnosis is made through physical examination.
A small abscess may heal on its own, through the body's immune system. But some will need to be drained or lanced in a medical provider's office so that the pus can be cleaned out. Antibiotics are usually prescribed.
Keeping the skin clean, and using only clean clothes and towels, will help to make sure that the abscess does not recur.
Top Symptoms: rash with bumps or blisters, red rash, red skin bump larger than 1/2 cm in diameter, pus-filled rash, rash
Symptoms that always occur with skin abscess: rash with bumps or blisters
Urgency: Primary care doctor
When and how to treat hard lumps on the scalp
Treatments for hard scalp bumps can begin at home as long as symptoms are not severe. However, see a physician for further medical treatments if symptoms persist.
Try the following treatments at home to address your symptoms.
- Warm and cold compresses: Compresses can help reduce pain and swelling if your scalp bump is due to infection or trauma.
- Pain medications: Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) or aspirin can help reduce pain, swelling, and redness. Acetaminophen (Tylenol) can also help with pain and fever but does not treat swelling and redness.
- Fluid intake: If your scalp bump is due to an infection, increase your fluid intake to help fight the infection, especially if you also have a fever.
When to see a doctor
Some scalp bumps are treated with home remedies and others require a physician's care, especially if you notice any of the following.
- Severe, sudden, or worsening pain and/or swelling
- Nausea and/or vomiting
- Redness that is worsening or spreading around the bump
- Change in vision, dizziness, or sudden/severe headache following a head injury
Change in shape, size, or color of a scalp bump over time
Your physician may recommend the following treatments.
- Incision and drainage: If your scalp bump is due to an infection and pus is collecting under your skin, a small hole (incision) in the skin overlying the bump can allow pus to drain.
- Antibiotics or antifungals: An antibiotic or antifungal in pill or cream/ointment form can fight the infection if the scalp bump is due to a bacterial or fungal cause.
- Surgery: If the scalp bump is due to abnormal growth of cells, a physician may recommend surgery to remove the bump to determine whether the growth is cancerous or not.
FAQs about hard scalp bump
Why is my scalp bump painful?
The pain you’re feeling depends on the cause of the scalp bump. Scalp bumps due to an infection may cause pain as the body responds to alert you of illness.
When is pain considered serious after bumping my head?
If your scalp bump is due to trauma, such as bumping your head, the pain you’re feeling is most likely the aftermath of the damage to the area in and around the bump. If your pain doesn’t get any better or gets worse, see a physician. If your scalp bump appears after trauma and is associated with severe pain or a headache, see a physician immediately.
Will my scalp bump go away on its own?
It depends. If your scalp bump is due to abnormal cell growth, it might stay the same, grow, or shrink. If it is due to an infection, it might go away on its own as your body fights the infection, or might go away with over-the-counter non-steroidal anti-inflammatory drugs like ibuprofen (Advil, Motrin).
Do scalp abscesses ever resolve on their own?
If your scalp bump is due to an infection and is causing a collection of pus (an abscess), it might go away, but usually, this requires drainage by a physician. See a physician for any bump that persists or grows over time.
Why is my scalp bump growing?
Your scalp bump may be growing due to fluid or blood collecting in and around the area of the bump. If your scalp bump is due to trauma, swelling around the injured area is common, but this swelling should decrease over time. A scalp bump due to infection may grow as pus collects in the bump under the skin or as lymph nodes enlarge in reaction to the infection. A scalp bump can also grow if abnormal cells or protein (like keratin) build up. These cells can be cancerous or non-cancerous. See a physician for any scalp bump that grows quickly or changes color or shape.
Questions your doctor may ask about hard scalp bump
- What color is the bump?
- Any fever today or during the last week?
- Are you experiencing a headache?
- Do you feel pain when you touch the bump?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Dr. Maina graduated from Princeton University (BA, 2013) with a degree in psychology and received her medical degree from the University of Pennsylvania Perelman School of Medicine. She is currently a resident physician in Otolaryngology at the University of Pennsylvania affiliated hospitals. After graduating from Princeton, she spent a year researching embryonic gene expression with the Center for Research on Reproduction and Women's Health at UPenn. She also received a grant from the National Institutes of Health to study abnormal innate immune responses and taste-related genes in chronic sinus infections. In her free time, she enjoys cooking, reading, listening to podcasts, and finding new DIY décor projects.
- Skin and soft tissue infections. American Family Physician. 2015;92(6):online. AAFP Link
- Folliculitis and carbuncles. Massachusetts General Hospital. Massachusetts General Hospital Link
- Cellulitis. U.S. National Library of Medicine: MedlinePlus. Updated August 30, 2016. MedlinePlus Link
- Abscess. U.S. National Library of Medicine: MedlinePlus. Updated May 2, 2016. MedlinePlus Link
- Ringworm. American Academy of Dermatology. AAD Link
- Melanoma. American Academy of Dermatology. AAD Link
- Basal cell carcinoma. American Academy of Dermatology. AAD Link
- Cysts. American Osteopathic College of Dermatology. AOCD Link