Boils are bad enough as a one-off — if you have been developing furuncles repeatedly, you're likely quite desperate to be rid of them and to find out what caused them in the first place.
Refresher Course: What Are Boils?
Boils are infections that begin deeply in a hair follicle and surround it completely. They're usually caused by the bacterium Staphylococcus aureus , and they start off as a slightly tender red bump on the skin. As a boil matures, it will become bigger and tighter and develop a pus-filled head. The skin around the boil may be slightly inflamed and hotter than the rest of the skin, and most boils will spontaneously erupt within about two weeks. 
Carbuncles, meanwhile, are clusters of boils joined together under the skin. These monsters can grow rather big, and are characterized by several yellow-tipped, pus-filled heads, rather than just the one .
Boils Don't Usually Require Medical Attention
Boils are quite common — Staph bacteria are often present on the surface of your skin and can enter through little nicks and grazes, sometimes so small that you don't even realize you have them. Boils, also called furuncles, are usually nothing to worry about. Rather than calling a doctor, most people can take care of the skin abscess themselves with the help of simple home remedies for boils:
- Take an over-the-counter painkiller such as Ibuprofen or acetaminophen (Tylenol/Paracetamol) if you are in discomfort.
- Do not squeeze or otherwise try to open your boil, to reduce the risk of infection and scarring.
- Apply home-made warm, moist compresses to your boil for around 20 minutes a few times a day.
- Once the boil begins draining, apply a sterile gauze to keep the area clean and to prevent contaminating other people or other parts of your own body.
- Wash the area with antiseptic soap twice a day.
- Do not reuse or share washcloths and towels. 
Nonetheless, many people do consult their family doctors when they suspect they have a boil (and there's certainly nothing wrong with that). It's a good thing they do, actually, because it is thanks to them that British researchers were able to determine that around 10 percent of people who have had a boil develop another boil within 12 months.  Suffering from recurrent boils is, incidentally, another reason to call your doctor.
Who Is At Risk Of Recurrent Boils (Furuncles)?
The UK study mentioned above identified the following risk factors for recurrent boils among the study participants:
- Being a young adult of low socioeconomic status
- Being obese
- Suffering from diabetes
- Suffering from chronic skin diseases such as eczema, psoriasis, or hidradenitis suppurativa
- Being a smoker
- Having used antibiotics within six months of your first consultation for boils 
Though boils are generally believed to be more common in men , this study found that women younger than 65 were actually more likely to suffer from recurrent boils . The fact that women are more likely to be seen for recurrent boils after they've entered puberty and before menopause suggests that hormones may play a role in recurrent boils as well .
People with compromised immune systems have been found to be at risk of recurrent boils in other collected data as well — it's not just people with diabetes who are more likely to suffer from boils time and time again, but also, for instance, those who are HIV positive.  In case the fact that the UK researchers identified recent antibiotic use as a risk factor for recurrent boils baffles you, we should probably add that this, too, may be due to the fact that folks with weakened immune systems are more likely to need antibiotics. (Or in other words, this is probably a matter of "correlation" rather than "causation".)
Nonetheless, seemingly completely healthy people can certainly develop boils — and some "victims" will undoubtedly find the suggestion that "socially deprived" people living in overcrowded conditions are more likely to encounter this problem quite insulting.
At the end of the day, you'll find risk factors for recurrent boils interesting only to the extent that they can help you wave your repeated furuncles bye-bye, so let's take a look at ways to treat them.
Recurrent Boils: What Can I Do To Break The Cycle?
Your doctor may well suggest that you be screened for conditions associated with recurrent boils, such as diabetes . A sample of the fluids from your boil(s) should also be sent to a lab so a culture can be studied, and your healthcare provider will know whether your boil is caused by MRSA. 
Besides that, if you are colonized with either S. aureus or MRSA (methicillin-resistant Staphylococcus aureus), one or more of the following decolonization regimens may be recommended — in addition to the commonly used incision and drainage procedure in which your doctor makes a small opening to allow the pus to drain out:
- Education — boils are contagious, and it's important that you don't reinfect yourself by allowing the fluids present in the boils to come into contact with items such as bed sheets, towels, and clothing, which you later reuse.
- A topical antibiotic, most often Mupirocin, to help get rid of the bacteria from your skin.
- Body washes with the antiseptic chlorhexidine. 
In addition, you may be prescribed systemic antibiotics for boils, most often Flucloxacillin, Macrolide, or Tetracycline . These antibiotics sometimes achieve success where other treatments do not.
What It Really 'Boils' Down To
Boils are common, but recurrent boils are much less so. Repeated furuncles are a sign that something isn't quite right with your body, and that whatever treatment you've been using until now isn't enough to get rid of the boils in the long-term. Nobody should have to suffer from this pest over and over again — and to be free of boils from now on, you may have to ask your doctor to use more radical measures.