An abscess is an encapsulated accumulation of pus in a non-preformed body cavity. It is caused by inflammatory melting of the tissue skin. The pus consists of:
- Bacteria
- Dead cells and
- Immune defence cells (white blood cells)
The inflammatory reaction is caused by various bacteria, which are often part of the normal skin flora, and can penetrate the skin through injuries and cause inflammatory reactions there.
Due to the accumulation of pus, the abscess exerts pressure on the surrounding tissue and can cause pain. Abscesses vary in size between small, barely visible, round nodules and areas as large as the palm of a hand. When an abscess forms on a hair root, it is called a boil, when several boils merge together, it is called a carbuncle.
In principle, abscesses can develop anywhere: However, they most frequently occur in or under the skin, as the skin is usually the first to be confronted with potential pathogens. In contrast, an empyema is an accumulation of pus in an already preformed body cavity. (e.g. paranasal sinuses)
- Brain
- Liver
- Anus (anal abscess)
- Gums
- Face
The superficial abscess shows typical skin reactions, as is common in an inflammatory reaction, with redness, swelling and overheating of the skin above the abscess.
In some cases the accumulation of pus is also visible as a white spot/white area. Often there is also pain, which increases mainly due to pressure (in the case of anal abscesses when sitting or defecating). Depending on the size of the abscess, it can look almost like a pimple.
Deeper abscesses can initially be completely asymptomatic until they open up and the pathogens spread through the body. Then typical clinical symptoms with fever and a general feeling of illness occur, after which one should consult a doctor at this point at the latest. If the pathogens spread in the bloodstream, there is a risk of blood poisoning (sepsis), which is accompanied by a very severe general feeling of illness and high fever.
If untreated, sepsis can lead to multiorgan failure and thus be fatal and is therefore a very serious disease that must be treated with antibiotics as soon as possible. Therefore, an abscess should always be treated early. Clear signs for an urgent treatment are Often the terms “abscess” and “boils” are used as synonyms.
But there are some clear distinguishing features. – Fever
- Increase in size of the abscess
- Distinct redness and
- Pain in the abscess area
The inflammatory reaction on the skin can cause redness and itching on the skin. In general, however, itching is not a leading symptom of the abscess but rather rare.
More often pain, swelling, pressure sensitivity and pus are described, as well as systemic symptoms such as fever, fatigue and headache and aching limbs. The majority of abscesses occur without an obvious cause. Usually bacteria are the triggering factors of an abscess.
In response, the body activates its defense system and the white blood cells fight the pathogens, which causes pus to form. Finally, the body forms a capsule around the accumulation of pus to prevent the abscess from spreading further in the body. Often, genera of Staphylococcus aureus can be isolated from the abscess.
But also streptococci that belong to the normal skin flora, tuberculosis bacteria or even fungi can cause inflammatory reactions and thus abscesses. The pathogens can penetrate the skin through the smallest of injuries and lead to the formation of an abscess. However, pathogens can also contribute to the formation of abscesses by penetrating the skin.
More rarely, abscesses occur in the context of chronic inflammatory diseases such as Crohn’s disease. – Surgeries
- Foreign body or
- Syringes
In addition, there are a number of factors that favour the development of an abscess. These include, among others: As a protective mechanism, the body builds a protective barrier around the abscess to contain the spread of the pathogens.
This protective wall consists of granulation tissue containing numerous defence cells and is called the abscess membrane. The pus inside the abscess cavity consists mainly of dead cells, bacteria and defence cells (neutrophil granulocytes). In addition to these common abscesses there are also the “cold abscesses”.
No pathogens can be isolated from these. The reasons for this abscess formation are not yet sufficiently explained. – already pre-damaged skin (e.g. in neurodermatitis or psoriasis)
- A weakened, endogenous defence
- Metabolic diseases like diabetes mellitus
- Poor care of wounds
- Poor personal hygiene
- Chafing clothes
- An inflammation of the glands in the anal canal (the proteal glands)
