Overview 

Have you ever encountered “large pimples” on your buttock and never knew what’s the cause of it? There is no need to fear, as this can happen to almost anyone. 

These “large pimples” are not actually pimples. In fact, they are known as boils. Unlike pimples, which grow on the skin surface, boils develop under the skin due to bacterial infection in the hair follicles. They are pus-filled bumps which can swell up to 5 centimetres in size. Not just on the buttocks, boils can develop anywhere across the body, primarily affecting regions that are exposed to more friction and moisture due to sweat buildup. Boils often occur due to improper care of personal hygiene and often recover naturally over a short period of time. However, medical treatment will be required if the boils develop periodically and persist for a longer duration. 

Understanding boils 

A boil, also known as a furuncle, appears as a swollen, pus-filled bump under the skin. You could think of it as a large pimple, except it develops deeper under the skin and is often a lot more painful than the usual pimple. Boils are often a result of a bacterial infection of hair follicles. The most common bacteria causing this skin infection is Staphylococcus aureus.¹

Initially, boils are presented as red, swollen bumps. As the infection progresses, skin tissues in the bumps begin to die, leaving behind a pus-filled lesion (skin abscess).¹ Sometimes, though quite rarely, severe infections lead to the formation of carbuncles, which are basically a cluster of boils. Carbuncles are a lot deeper under the skin and can be way more painful than individual furuncles. People affected by carbuncles usually experience other inflammatory symptoms such as fever, chills and fatigue.¹

Here is a glance at the manifestations of a boil: 

• Affected areas will be red (or purplish at times), swollen and firm
• Feels warm when touched
• Increase in size over time. They can potentially grow bigger than five centimetres (diameter)
• May be itchy and often painful when squished
• Filled with yellowish pus

Boils can form almost anywhere on our skin, but some areas are more prone to boiling, such as our face, armpits, groin, back of our neck, buttock, bottom of our thighs, and genital areas. These areas, especially the butt, typically favour boiling as they have more skin folds and where we tend to sweat a lot and experience friction. This warm and moist environment becomes ideal for bacteria colonisation, thus promoting the chances of boiling or recurrent furunculosis on the buttocks.²

Causes of boils on the buttocks 

Bacterial infections

Staphylococcus aureus bacteria commonly reside on our skin and in the linings of our nostrils, but they don’t usually cause any harm. Infection occurs when the bacteria invade the skin through minor cuts or abrasions, leading to the formation of boils.³ This explains why buttocks are more susceptible to the growth of boils. For instance, constant friction resulting from wearing tight clothing or from sitting too long can cause abrasions on the skin, which gives the bacteria the opportunity to invade the inner layers of the skin, thus inducing an infection.

Risk factors

Anyone and everyone of all ages can have boils. Some conditions can potentially put a person at higher risk of developing boils. For example: 

• Poor hygiene 

Regions that are highly susceptible to boiling, especially the buttocks, are usually places that are easily neglected when it comes to cleaning. Moreover, areas like the back of the neck, armpits and the groin have more skin folds. If not adequately cleaned, dead skin cells and sweat can accumulate in the creases, subsequently increasing the risk of contracting the infection.⁴ 

• Weakened immune system

People with weakened immune systems are generally more vulnerable to boiling. In the event of an infection, the immune system initiates appropriate responses to kill the invading pathogen (bacteria in this case). Hence, immunocompromised individuals will have difficulties fighting infection and stand a higher chance of experiencing recurrent boils (furunculosis) or developing carbuncles.^1,3

• Chronic skin conditions

Skin-related diseases such as eczema cause flare-ups on the skin, making the skin barrier inflamed and damaged. This provides an easy entry for bacteria to enter the skin layers.¹

• Diabetes

Diabetic individuals have a higher tendency to develop boils due to elevated blood glucose levels. Elevated blood glucose levels impede blood circulation to the skin and weaken the immune system, thus promoting the activity of bacteria.^5,6

• Constant friction and pressure

Due to tight clothing and long periods of sitting, buttocks are exposed to more friction and pressure, which can result in abrasions and irritations in the skin, thus increasing the risks of infection. 

Treatment options for boils 

Home remedies

Most boils will recover naturally over time. When the pus drains out from the boil, it is a sign that the boil is healing. One should never squeeze the boil to let the pus out as it may lead to more infections. Some tips that you can do to speed up the recovery process at home are: 

• Warm compresses

Get a warm-soaked (ideally salt water) clean cloth and press it gently over the boil for approximately 10 minutes several times a day. This should accelerate the recovery and also help relieve pain. 

• Proper hygiene

It is also essential to keep the affected area dry and clean at all times. When pus is discharged, areas around it should be cleaned thoroughly using antibacterial pus to prevent the spreading of infection. 

• Over-the-counter treatments (OTC)

Antiseptic creams and ointments can be obtained from local pharmacies. After applying treatment, cover the affected areas with sterile dressings to prevent contamination and promote fast healing. The dressings should also be changed regularly. “Drawing salve” is an ointment that can also be purchased over the counter, and it helps to draw pus out from the boil.¹

Medical treatments

Antibiotic prescriptions may be necessary when recurrent boils occur or when the boils persist and develop into a carbuncle. In more severe cases, intravenous (IV) antibiotic treatment might be needed. Healthcare professionals will perform surgical procedures such as incision and drainage for pus drainage in carbuncles. Painkillers like paracetamol or ibuprofen can also be consumed to alleviate the pain.¹

Preventive measures

Good personal hygiene is the key to lowering the risk of developing boils. Here are some preventive measures that we should all practise on a daily basis to prevent boils.^2,3

• Regular baths with soap, especially after sports or after sweating a lot
• Wash your hands regularly with antibacterial soaps, especially after touching a boil
• Avoid picking or scratching any skin injuries to avoid bacterial infection
• Change towels and bed linens regularly and avoid sharing towels with other individuals
• Practise a healthy lifestyle by exercising regularly and maintaining a balanced diet, as it contributes to a healthy immune system
• Avoid wearing tight clothing. Wear loose and breathable clothing instead to reduce friction

When to see a doctor 

If you experience symptoms such as: 

• Recurrent boils 
• Persistent boils (> 2 weeks)
• Immense pain
• Fever, chills and fatigue 
• Carbuncles (cluster of boils)
• Or if you have boils and you have an underlying condition (diabetes, immunocompromised, etc.)  

You should consult your GP immediately. Thorough clinical examination and lab diagnostic procedures, such as pus swabs, will be performed to determine the type of bacteria causing the infection. Occasionally, blood and urine tests will be conducted to assess blood glucose levels and detect if the infection has spread.^1,2 Recurrent boils are often a symptom of methicillin-resistant Staphylococcus aureus (MRSA) infections. MRSA infections can progress into more severe complications, including sepsis, meningitis, respiratory infections, etc. and can cause death if left untreated. Laboratory testing of pus samples also helps healthcare professionals to determine which antibiotics should be prescribed to the patient, as MRSA infections are resistant to certain antibiotics.²

Summary 

Boils on the buttocks are a very common phenomenon among all individuals. They usually heal over time, even without treatment. Warm compresses and antiseptic treatment are typically sufficient for the recovery of boils. However, in some scenarios, one might encounter severe infections where medical care is required to eradicate the infection completely. Some standard protocols include antibiotic treatment and minor surgeries to eliminate the pus (incision and drainage). Further diagnostic tests will also be conducted in case of any underlying complications. Proper personal hygiene should be practised at all times to lower the risk of developing boils. If you experience persistent boils or any of the symptoms listed, medical advice should be sought immediately as it may be a sign of a more severe condition.