Furuncle: what it is, what it looks like and how it develops

You have found a hard, painful formation on your skin and want to understand what it is. Let's go through it step by step: what a furuncle looks like, what complications can occur and when a doctor is needed.

What a furuncle is

A furuncle is an acute purulent-necrotic inflammation of the hair follicle, sebaceous gland and surrounding connective tissue, most often caused by Staphylococcus aureus. In everyday language it is called a boil. It is a hard, painful formation with pus; sometimes the pus drains out, and the skin around it is red.

What causes a boil

Bacteria get into the skin through a cut, scratch, minor injury or a spot where shaving went wrong. After that, everything depends on the conditions. Furuncle development is promoted by contaminated skin, increased sweating and sebum production, exposure to cold, metabolic disorders and reduced immune activity.

The risk is higher with diabetes, HIV, eczema, obesity and malnutrition. The use of certain medications, such as steroids, and close contact with a person who has furuncles also matter. Friction and moisture in skin folds are important too.

How a furuncle develops

A furuncle often starts as an itchy or painful spot. Then a painful follicular pustule with necrosis in the center appears on the red skin — the core of the furuncle. After the necrotic tissue is shed, a wound remains, which heals with a scar. In most people, a furuncle resolves on its own.

Furuncle and carbuncle: what is the difference

When several furuncles together form a group, it is called a carbuncle. This is a purulent-necrotic inflammation of the skin and subcutaneous tissue around a group of hair follicles and sebaceous glands. Carbuncles are less common and occur more often in middle-aged men.

What complications occur and where a furuncle is dangerous

Complications depend on the location and how advanced the condition is. Inflammation of lymphatic vessels and nodes is possible (lymphangitis, lymphadenitis). Next is phlegmon: on the head it is dangerous due to sinus thrombosis, on the neck due to purulent spread into the mediastinum and mediastinitis, and on the limbs it spreads through intermuscular and interfascial spaces. The extreme complication is sepsis.

Separately about the face. With a furuncle in the area of the upper lip, nose and cheeks, purulent meningitis and sepsis are possible. Most often furuncles appear on the neck, back of the head, face, back, thighs and genital organs.

When to see a doctor about a furuncle

The time reference is two weeks. If the furuncle persists longer and your attempts do not help, you need a doctor. A doctor is also needed when furuncles appear again or there are several next to each other, that is, it is a carbuncle.

A prompt consultation is needed if the furuncle is on the face, the skin around it is hot, painful and swollen, if you have chills or feel feverish, if your immunity is weakened — due to steroids, diabetes or another condition.

The doctor examines the formation and decides whether a procedure to drain the pus is needed. Diagnosis begins with an examination and questions about symptoms. For skin infections in general, a skin culture is possible — a swab, scraping or tissue fragment; sometimes blood tests are ordered.

• How long healing will take in my particular case
• Whether a culture is needed and what it will show
• What changes should bring me back
• Whether the furuncle is related to diabetes or another condition

A furuncle by itself is not a reason to call an ambulance; 103/112 — if signs of sepsis or spread of infection appear against the background of a furuncle, especially one located on the face.

This material is for reference: it helps to understand what a furuncle looks like and how it develops, but it does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer