What is the cause of boils

Follicle inflammation and boils

Hair follicle inflammation (Folliculitis): superficial, mostly bacterial inflammation of the hair follicle, especially on the face (in men in the beard area), on the neck and on the buttocks. Sometimes inflammation of the hair follicle develops into encapsulated collections of pus (boil).

Infectious hair follicle inflammation and its consequences (boils, carbuncles) are treated with local disinfection and / or antibiotics, depending on the extent. The doctor sometimes has to surgically open boils and carbuncles.

Leading complaints

  • Hair follicle inflammation: one or more reddened painful nodules with a yellowish-green pustule around a hair, often surrounded by a reddish fringe
  • Boils: inflamed, red, tender nodule, often with a pus plug in the middle.

When to the doctor

In the next few days, if inflamed follicles or boils

  • does not heal on its own
  • occur in large numbers.

Today if

  • There are underlying diseases in which the general immune system is weakened e.g. B. diabetes, AIDS
  • Fever and fatigue are added
  • a boil occurs on the face, particularly on the nose and upper lip.

The illness

Causes and Risk Factors

Inflammation of the hair follicles is usually caused by infection, either spontaneously (mostly) or as part of a purulent inflammation in another organ (rarely). The main pathogens are bacteria (especially Staphylococcus aureus, less often Klebsiella, enterobacteria), but also fungi (Malassezia) and parasites (e.g. Demodex) can infect a hair follicle. Triggers or risk factors for infectious hair follicle inflammation are considered

  • poor hygiene, e.g. B. after shaving
  • Use of whirlpools
  • damaged skin, e.g. B. in the context of neurodermatitis or acne
  • Diabetes, blood cancer (leukemia) and kidney diseases (here mainly as furunculosis).

However, inflammation of the hair follicles is sometimes also non-infectious. Possible triggers are e.g. B.

  • Medicines such as bromoderm or tyrosine kinase inhibitors
  • very oily skin care products such as petroleum jelly or massage oils
  • (mostly professional) contact with tar and oil
  • mechanical irritation, e.g. B. by shaving the lower legs.

In addition, disease-related hair growth disorders or cornification disorders of the skin lead to inflammation of the hair follicles, in some cases they develop for no apparent reason, i.e. H. idiopathic.

Localization and course

Wherever there is hair, the hair follicles can also become infected. Inflammation of the hair follicles is preferred on the neck, face, armpits, buttocks, arms and legs.

If the inflammation of the hair follicle spreads to the surrounding tissue, a boil develops. The appearance of numerous boils on different parts of the body in bursts is called furunculosis.

When several boils melt together, a large, very painful one is created Carbuncle, characterized by swellings as hard as a board with perforations of pus. Those affected suffer from fatigue, fever, chills and painful swelling of the lymph nodes.


In the case of a carbuncle and improper treatment of a boil, there is a risk that the causative pathogens from the hair follicle enter the bloodstream and cause life-threatening blood poisoning (sepsis). Boils in the lip, nose and cheek area are particularly dangerous because the germs can easily reach the brain via the bloodstream or lymph drainage from the nasal area and cause life-threatening infections there.

Note: Do not let yourself be tempted to squeeze around purulent inflammations in the facial area. Instead, see a doctor on the same day.

Diagnostic assurance

The clinical picture easily guides the dermatologist to the diagnosis; if in doubt, he takes a smear from the base of the pustule and has the pathogen detected in the laboratory with the help of a culture. In the case of folliculitis in the beard area, he also uses a plucked beard hair.

In the case of furunculosis or carbuncles, the doctor usually has a blood count, blood sedimentation rate (ESR) and blood sugar checked in order to rule out an underlying disease such as diabetes mellitus or leukemia.

Differential diagnoses. Acne, fungal infections of the skin and skin lesions from syphilis often resemble the skin symptoms of folliculitis.


Infectious hair follicle inflammation

Treatment is often not required in mild cases. The doctor only disinfects the affected area (e.g. with Dermowas® solution) and possibly opens the pustules in the case of pronounced forms. Then he prescribes moist antiseptic compresses or disinfecting creams or lotions, sometimes also antibiotic creams, e.g. B. with fusidic acid. In the case of widespread infections, it is necessary to use internal antibiotics. The doctor often gives these intravenously in the first few days of treatment, later switching to tablets. Frequently used active ingredients are cephalosporins or clindamycin.

If the beard area is affected, the doctor recommends first avoiding shaving and treating the skin with antibacterial cleaning solutions. In addition, the razor should be cleaned with 70% isopropanol. Mild forms often heal with this treatment. In the case of chronic folliculitis in the beard area, the doctor often prescribes a low-dose cortisone cream for 2–3 days. If the therapy is unsuccessful, internal antibiotics are used for up to 3 weeks, in persistent cases also isotretinoin (e.g. Aknenormin®).

Boils and carbuncles

The doctor opens a ripe boil or carbuncle with a scalpel and then inserts strips of gauze soaked with an antibacterial solution. These have a germicidal effect and prevent premature wound closure. Like the dressing above, they must be changed daily. Stubborn or recurring boils occasionally make it necessary to take an antibiotic, and in the case of severe inflammatory skin reactions, the doctor will also prescribe anti-inflammatory agents such as diclofenac.

If you have a fever, signs of inflammation in the blood (leukocytosis), large facial furrows and a weakened immune system, hospitalization is required. Here the necessary antibiotics are administered intravenously.

Non-infectious follicle inflammation

In the case of non-infectious hair follicle inflammation, the doctor usually first treats the cause, e.g. B. the underlying skin disease, or trying to eliminate the triggers (medication, improper skin care). Antibiotic therapy is often not very promising. In order to reduce the skin inflammation, the doctor may prescribe cortisone ointments for a short time.

Your pharmacy recommends

What you can do yourself

If the boil is still immature, the discharge of the purulent contents can be promoted with moist compresses and ointment (e.g. Ichtholan® ointment with ammonium bituminosulfonate). After that, the inflammation usually subsides quickly - but there is a risk that the bacteria that emerge with the pus will spread. It is therefore advisable to carefully disinfect the surrounding skin and hands after contact with an open boil and to wash towels and bedding with hot water.

Complementary medicine

Hydrotherapy. Fango packs, quark compresses or poultices with potassium permanganate help with the onset of swelling. Hot compresses and chamomile baths are suitable for ripening the boil. Healing earth pads (mix healing earth with 1 l of water or vinegar, apply half a centimeter thick to the affected skin area, remove after about half an hour) reduce the itching and shorten the healing process. If boils occur repeatedly, chamomile-sulfur baths with brine are indicated.

Phototherapy. Irradiation with red light or with germicidal UV light for 10 to 15 minutes sometimes has a positive effect, as does irradiation to generally strengthen the body's defenses.

Herbal medicine. For external use - also over night - we recommend ointment pads with Mercurialis perennis (forest ragweed). They act as a pulling ointment and the boil swells. Essential oils and resins made from rosemary and myrrh are disinfecting and can, when applied in the form of ointments, promote the healing of superficial inflammations. To accelerate the ripening process, you can use linseed sachets (150 g of ground linseed is boiled with half a liter of water and then squeezed out), chamomile tea sachets and hot hay flower sachets (from the pharmacy). Arnica compresses, chamomile cream (Kamillosan®) or echinacea ointment or tincture also accelerate the healing process. Preparations made from coneflower (Echinacin® Madaus) or combination preparations such as Esberitox® are suitable for stimulating the immune system.


If you are prone to boils, it is best to wear airy, loose-fitting clothing, as both heavy sweating and constant chafing promote the formation of boils. Frequent washing of clothing at high temperatures reduces the risk of re-infection from bacteria that remain there, and careful disinfection after each shave prevents small injuries from turning into purulent inflammation.

If the boils recur, an autovaccination may help. This individual conventional medical procedure uses pathogens from the patient's pus. When killed, "tailor-made" vaccines are made from them and injected under the skin in increasing doses. However, the effectiveness of auto vaccination has not (yet) been scientifically proven.


Dr. med. Arne Schäffler, Dr. Bernadette Andre-Wallis in: Health Today, edited by Dr. med. Arne Schäffler. Trias, Stuttgart, 3rd edition (2014). Revision and update: Dr. med. Sonja Kempinski | last changed on at 10:40

Important note: This article has been written according to scientific standards and has been checked by medical professionals. The information communicated in this article can in no way replace professional advice in your pharmacy. The content cannot and must not be used to make independent diagnoses or to start therapy.