Painful Lump under armpit: Common Causes, Diagnosis, and Treatments

Lumps under the armpit can be painful, painless, hard or even soft. They can also be dangerous or harmless. The best treatment depends on the cause and how severe the lump is.

In most cases, a painful lump in the armpit occurs due to enlargement of lymph nodes. It can also be due to a cyst or other forms of bacterial infections. Poor shaving techniques may also be responsible.

Diseases such as cancer may begin with a painless hard lump in the armpit. It is therefore advisable that medical attention be sought if a lump in the armpit is to persist, increase in mass, be painless or cause other symptoms such as fever.

Lump under armpit due to viral, fungal and bacterial infections

Infections due to bacteria, fungi and viruses are common causes of lumps in the armpit. They include:


Infected skin on the armpit dies off and obstructs skin pores through which sebum is secreted. The skin covering the lump appears to be red, swollen and warm. Formation of pus causes pain and burning sensation.


This fungal infection is a common cause of painless lumps in the armpit. The fungus that causes the disease is found in dust and is mostly spread through inhalation.


Measles is a viral infection and highly contagious. Lymph nodes located in armpits usually swell in attempt to fight off the measles virus. Common symptoms include rash, high fever and cough. The symptoms manifest about 7 days after contamination.

Chicken pox

Chicken pox is a viral infection. It causes swelling of the lymph nodes, especially ones on the upper parts of the body such as the armpits and throat. Chicken pox is characterized by a rapidly progressing rash, sore throat and fever.

Herpes zoster

Also known as shingles, it is a viral infection caused by chicken pox virus. The chicken pox virus is triggered by factors such as stress and use of some medications. Shingles is characterized by a lump under the armpits, rash and fever.


Mumps causes swelling of the saliva glands. It is a contagious viral disease. Other than swollen saliva glands, the lymph nodes in the armpit may swell. Other symptoms include mild fever and pain in the neck. If not treated, active mumps may lead to a painful lump on the testicle and infertility in males.


This viral infection is sometimes referred to as the ‘kissing disease’. It is spread through saliva, and common in individuals below 30 years of age. Sore throat, fever and swollen lymph nodes are the common symptoms.

Cysts and boils

Cysts and boils are caused by bacteria infected acne. Acne develops when sebum is trapped in follicles. If bacteria gains access to the trapped dirt, boils and cysts may develop. Boils are usually painful. A cyst mostly forms a hard lump that is not painful.

Painful lump in armpit caused by diseases

The following diseases may cause a painful lump in armpit:


It is a viral disease that compromises the immune system. Among other symptoms such as frequent illnesses, the lymph nodes will swell to form painful lumps.


This is a cancer of the blood. It spreads to the lymphatic system and causes painful lumps. The disease is also characterized by general feeling of weakness (malaise) and rapid loss of weight (anorexia).

Cat scratch disease

As the name suggest, the diseased occurs after being scratched by a cat. A lump that hurts in the armpit above the scratched hand will appear after about 3 weeks.


A soft lump under the skin on the armpit may be a sign of lipomas. The lump will slowly keep increasing in size to about 2.5 inches. It is rarely painful and is benign.


Lymphoma is a cancer of the lymphatic system. It begins with a painless lump in one of the lymph nodes. With time, multiple lymph nodes will develop hard lumps that keep growing.

Other causes of lump under armpit


Allergies are forms of autoimmune diseases. These are diseases that make the immune system behave in an unexpected manner, by attacking harmless substances such as protein foods. Lumps due to allergic reactions are usually inflamed, red and itchy. A lump in the throat feeling after swallowing may also be caused by contact with an allergen. In such case, it will be accompanied by difficulties in breathing.


It is a common condition in female puberty transformation. It results in overgrowth of breast tissue. The overgrown tissue may be felt as a lump in the armpit. Fibroadenoma lumps in breast move when touched. The condition is not cancerous.


As a side effect, vaccination may cause red or swollen lump on the skin. It can also lead to lymph node swelling or a small lump under the chin.

Lump in underarm due to cysts and boils

Most cases of benign lumps in the underarms are caused by boils and cysts.


Boils are skin infections. They may begin in a sebaceous gland or in the hair follicle. A boil will result in a small lump which is usually very tender. The skin surrounding the lump will appear red and sometimes itchy.

Boils develop after staphylococcus bacteria enter blocked hair follicle. As the immune cells fight off the bacteria, the resulting commotion produces inflammation and pus. The pus causes tenderness, pain and burning sensation.

The face and neck are other common body parts that boils develop. It may also develop on the eyelid and cause a sore lump behind the ear.

In severe cases, boils may form in clusters, a condition known as carbuncle. Poor hygiene is attributed with most cases of boils. Other causes include; skin irritation or injury, diseases like diabetes, deficiencies in minerals or vitamins and compromised immunity.

Boils can be treated with antibiotics. Home remedies and treatment options will also encourage recovery.


A hard lump in the armpit that is painless is likely going to be a cyst. Cysts follow much the same process by which boils are formed. They are however formed much more deeply into the skin. The hardness is caused by keratin, a protein that fills a cyst as it grows. Keratin is also responsible for the bad odor and yellowish appearance of cysts.

Cysts are best left to heal on their own. In any case, they are neither harmful nor painful. Removing it at home is likely going to damage the skin surrounding it. However, it can be removed in a clinic by your doctor.

How to know if hard painful lump under armpit in females is cancerous

Breast lumps are common indications of cancer. It is for this reason that it is important to determine if a hard painful lump under the armpit in females is a sign of breast cancer. Below are tips that can help:

  • Breast cancer lumps keep gaining mass and therefore increasing in size. If the lump has persisted for long with no sign of evolution, it is less likely to be cancerous.
  • Cancerous lumps are usually hard and rarely painful. You can try moving the lump with your fingers. If the lump feels soft and movable, it is less likely to be cancerous. If it however is fixed, hard and neighboring other tiny lumps, there are all reasons to think it cancerous.
  • A rapidly growing, painful lump that causes skin redness, tenderness and skin burning is more a bacterial infection than it is a sign of cancer. Cancer lumps grow by rapid cell division. This means that evolution will not occur overnight.
  • Look for other possible causes of lump under armpit. Cancer lumps appear as if from nowhere. With time, they are likely to spread to other body parts.

If you can’t seem to be certain whether a lump in your armpit is a sign of breast cancer or not, consult your doctor as soon as you can. When diagnosed early enough, cancer lumps are curable.

Treatment for lump under armpit painful symptoms

Lump under armpit painful symptoms can be treated through a number of ways. Diagnosis is in most cases necessary to determine the actual cause of the lump.

Physical examination, allergy tests, blood count tests, biopsies and X-ray will help your doctor estimate the most possible cause of the lump. After there, the best treatment will be prescribed.

Over the counter creams can be used to treat swollen painful lumps due to bacterial infections. Antibiotics are better options for severely infected lumps in armpit. In case of itchy or allergy symptoms, antihistamines will be prescribed.

Painful lumps in or near the armpit can be eased with pain medications. If caused by diseases or health conditions, your doctor will discuss the best treatment options available.

Treatment can also be done through self-care measures. For example, maintaining hygiene and keeping up with healthy diets will in one way of another fight lumps in armpit. Much the same can be said about learning about and avoiding potential allergens.

How to treat painful lump in armpit at home

At home, a number of options as well as home remedies can be used as treatment options for painful lump in armpit.

Soak a small towel in warm water and squeeze off runaway water. After that, compress it on the lump for about 10 minutes. The treatment will bring any pus to the surface and encourage healing.

Apply raw honey on and all around the lump. Let it stay for about 15 minutes and rinse off with fresh warm water. This treatment will not only help with swollen, painful lump but will also keep from bacterial infection.

Dilute apple cider vinegar with equal volume of water. Use a cotton ball or a washcloth to apply it on the lump in armpit. Rinse it off after 6 minutes. Apple cider vinegar reduces swelling and fights infection.

Dress the lump with vitamin E oil about three times a day. The oil is rich in antioxidants and vitamins that will encourage healing. The vitamin can also be taken in supplements or foods that contain it in abundance.

For a painful lump with signs of infection or swelling, try massaging aloe Vera gel all over. The gel will soothe the paining skin region and fight bacterial accumulation.

Turmeric is a strong anti-inflammatory home remedy. It Is In fact recommended as one of the foods that fight cancer. Turmeric can be applied directly or be taken in drinks.

Use lemon juice as an antiseptic. Microbes will not survive in the acidic environment created by applying lemon juice on a painful lump in armpit.

Before attempting to remove a lump in the armpit at home, it is best to be certain that it has resulted from a benign condition. If otherwise, let your doctor be the one to direct which method is to be used for removing the lump and its symptoms.