Do you have a very painful white abscess on a finger or toe but you don’t know how to treat it? It may be whitlow, a form of abscess caused by a bacterial infection. If you suffer from it, it is imperative to consult a doctor. But how to recognize a paronychia and what are the complications? Le Figaro takes stock with Professor Philippe Humbert, specialist in dermatology and internal doctor, author of the book “Do you have a good doctor? (Fayard, 2018) and “Your skin tells me everything about you” (Les éditions Sydney Laurent, 2020).

Paronychia is a skin infection that manifests itself by the formation of an abscess on the level of a finger or a toe. It usually occurs when an open wound becomes infected. “The particularity of paronychia is that it is very painful,” explains Professor Humbert. The symptoms appear successively. At the inflammatory stage, within 2 to 5 days following the trauma to the finger, swelling (swelling) around the nail can be observed, which tends to stretch the skin considerably. Redness, a sensation of heat as well as pain of varying intensity are then felt. “These are pains” which hit “or” which beat “a bit like a dental abscess”, describes the dermatologist. If not treated at this time, whitlow progresses to form an abscess filled with pus.

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Paronychia is caused by a bacterial infection of the skin tissue. The main culprits are staphylococcus aureus or hemolytic A beta streptococcus. However, paronychia can also be caused by the bacillus pyocyanin which belongs to the digestive tract, or to the yeast of the Candida albicans species, present in the digestive and gynecological mucous membranes. “For the area to become infected, you need an entry point for the bacteria. Typically it will be a small open wound around the nails, too aggressive manicures, tearing of skin, blisters, splinters, insect bites or even bites. However, anti-infective molecules naturally present on the skin, defensins, will tend to limit penetration. This attracts an arsenal of immune cells – mostly white blood cells and platelets – which cluster around the infectious agent to fight it off. Accumulating, the white blood cells form pus in this closed space, which visually gives the famous whitlow abscess.

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You are not at risk of developing paronychia every time you tear off a small piece of skin around a fingernail. This risk increases if you do it very frequently, but some people will be much more susceptible than others due to several contributing factors:

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Untreated paronychia is dangerous because it can be accompanied by serious complications. One of the most severe is infective endocarditis, which results from the spread of germs to the heart valves. The infection results in immediate symptoms such as chills and fever or even severe weight loss after a few weeks. “Without treatment, you can die,” says Professor Humbert.

In other cases, whitlow microbes can lodge in the joints and in particular infect the intervertebral discs, that is to say the cartilage between each vertebra of the spine. We are talking about spondylodiscitis. The main symptoms are also fever and chills in addition to intense pain in the spine. More rarely, the infection reaches the brain by forming cerebral abscesses.

There is a non-zero risk of transmitting the infection to other people. “In 2005, for example, in the town of Ornans, a person with whitlow on his finger cooked for all the participants in a bicycle race. The runners all ended up in hospital, diagnosed with severe gastroenteritis from eating staph-infected food. “, explains Professor Humbert.

In prevention, it is essential, if it is not already the case, to be vaccinated against tetanus because the bacterium at the origin of this serious disease (Clostridium tetani) is able to infiltrate by the same wound which caused paronychia.

To treat whitlow itself, it will first be a question of acting locally, in particular by the evacuation of pus (carried out by a doctor), the application of antiseptics (generally chlorhexidine or “solution dakin”, or hexomedin) and ointments containing antibiotics (fusidic acid, mupirocin). “At the same time, we can start a systemic treatment for 10 days. The most commonly used antibiotics are pyostacin or certain antibiotics from the penicillin family,” adds Professor Humbert.

If there is a complication, it must be taken care of by a specialist who will prescribe a specific treatment. “In the event of sepsis, when the infection spreads in the blood as for infective endocarditis or spondylodiscitis, the treatment takes place in the hospital using infusions for a minimum of two to four weeks”, finally warns the doctor.