Furuncle: what are the causes of skin inflammation? + What is a carbuncle

A furuncle is defined as a deep-seated inflammatory nodule with central suppurative tissue breakdown (collapse). It is caused by infection of the hair follicle.

The causative agent of the disease is Staphylococcus aureus. It occurs mainly with inadequate hygiene.

Furuncle is a skin disease caused by bacteria. In a narrower sense, bacterial skin diseases include infectious skin diseases that are caused by the immediate presence of bacteria on or in the skin.

In a broader sense, they include skin diseases that are a manifestation of an infectious disease but occur in other areas.

What about microorganisms on our skin?

The skin of a healthy baby is sterile in the womb. However, during birth, it is changed. It is contaminated with bacteria in the birth canal. So from the moment of birth, our skin is colonised and covered with a large number of micro-organisms.

During life, the amount of bacteria changes, as does their species composition. We have different amounts and types of skin bacteria on different parts of the body. Some bacteria colonise our skin permanently, some only for a short time.

There are two types of microbial community:

• resistant - their presence is permanent and they are beneficial to the host.
• transient - they only contaminate the skin for a certain period of time

Staphylococcus epidermidis makes up more than 90% of the stratum corneum flora. Staphylococcus aureus and other bacterial strains make up the remaining 10%.

Local microbial colonisation influences the skin's response to various injuries or infections. If there are changes in the composition of the skin microbiome, atopic eczema, psoriasis or vitiligo may develop.

Bacterial skin diseases are divided into two groups:

• superficial - affecting the epidermis and dermis
• deep - spreading to the subcutaneous tissue and musculature

Table 1: Superficial skin infections can be divided into two subgroups, namely complicated and uncomplicated

Furuncle is a contact infection. It can arise in the following ways:

• autoinfection (transmission from the patient's nasopharynx)
• transmission from the external environment (during hospitalisation)
• person-to-person transmission
• via parts of clothing contaminated with staphylococci

The bacteria enter the follicular duct from the external environment. They are most often found in the follicles of terminal hairs. In these follicles they multiply and cause extensive inflammatory changes by enzymatic action.

Furuncles occur mainly in patients with various diseases:

• consumptive diseases
• metabolic diseases (diabetes mellitus)
• congenital diseases
• HIV infection

The development of the disease may be conditioned by long-term treatment with glucocorticoids, immunosuppressants or cytostatic therapy.

Furuncle can appear on any place on the body where hair grows. It is most common on the neck, face, armpits, buttocks and legs. It mainly affects areas where there is friction.

Symptoms of the disease include:

• feeling of tension
• an erythematous nodule with swelling in the area
• central fusion
• soreness
• lymphangitis
• lymphadenitis
• slightly elevated temperature
• feeling of nausea

In the first stages of the disease, a creamy yellow vesicle the size of a grain of rice may be observed. Later, an inflammatory reddish nodule develops acutely. It is painful on pressure and swelling develops around it.

In many cases, the symptoms are accompanied by lymphangitis and painful lymphadenitis. In some cases, the patient may have a slightly raised temperature.

A yellowish crust gradually develops from the original vesicle, which is a sign of tissue necrosis. After a few days, central fusion occurs with increasing liquefaction and circumscription. At this stage, the furuncle is mature.

The liquefaction progresses closer to the surface. Subsequently, creamy-yellow pus begins to ooze out. Not every furuncle rolls to the surface. In such cases, its tense contents become very painful.

• Furuncle of the nose and upper lip

A furuncle is particularly dangerous if it is located above the junction of the corners of the mouth and the auricles. In this case, thromboses (sinus thrombosis) can occur.

• Furuncle of the upper lip

A furuncle of the upper lip does not tend to fuse. In this type of furuncle, extensive collateral inflammatory swelling of the face occurs. The danger of the disease lies in the risk of the causative agent entering the bloodstream and causing sepsis.

Warning signs include high fever, chills and a feeling of weakness.

• Furuncle of the nose

Nasal furuncle is caused by mechanical plucking of the hairs. For this reason, trimming of the hairs is recommended. This prevents injury to the gate sites.

• Furunculosis

Furunculosis occurs when one furuncle is replaced by another. Such replacement can last for several years. A common cause of the disease is contact infection. In some cases, the cause of furunculosis cannot be determined.

Causes of the disease include:

• underlying diseases - diabetes mellitus, cachexia, immune deficiency states
• dermatological diseases - eczema, scabies, pediculosis
• external treatments - oily ointments, tar treatment, occlusive dressings
• prolonged wearing of wet clothing

Do you know what a carbuncle is?

Carbuncle is one of the most severe forms of furuncle. It is characterized as a necrotizing infection of multiple hair follicles. Carbuncle is characterized by rapid growth. Compared to furuncle, its occurrence is much rarer.

It mainly affects men after the age of 40. It appears mainly on the neck and back.

The diagnosis of furuncle consists of the following steps:

• medical history
• physical examination (clinical picture, extent of changes)
• laboratory findings

Furuncle usually heals without complications, with a centrally retracted scar. Furunculosis can last for several years. The prognosis of the disease is favorable. When occurring on the face, it is determined with caution.