In general, folliculitis can have one origin infectious – therefore be caused by bacterial, viral or fungal infections – or not infectious, therefore induced by other causes.
Folliculitis: What is it? How long does it last? Causes and Treatment
There are different forms of infectious folliculitis, which differ mainly according to the etiological (causal) agent:
- Bacterial folliculitis (the most frequent form): typical infection that occurs immediately after epilation treatments (e.g. lasers) and depilatory treatments (simple shaving), or after mechanical injuries or chemical traumas to the skin responsible for the deformation of the hair shaft
- Fungal folliculitis: it is almost always caused by direct contact with objects or surfaces infected with fungi, such as common showers and changing rooms
- Viral folliculitis: typical of the area surrounding the lips
Based on the triggering pathogen and the characteristic symptoms, each type of infectious folliculitis is divided into several subcategories. Let’s see the main features, shown in the following table.
Not all types of folliculitis are caused by infections; there are, in fact, some variants that have nothing to do with infectious insults. Immunocompromised patients, suffering from obesity or dermatosis, and presenting evident skin lesions are concretely more at risk of folliculitis than healthy people.
By identifying the risk factors for the disease, other forms of folliculitis (not related to infections) have therefore been identified, which will be described below.
Tufted folliculitis – also known as doll’s hair folliculitis – is a variety of folliculitis decalvant, therefore typical of the scalp. It is characterized by the formation of pustules and inflamed areas in which there are tufts of hair emerging from the same follicular ostium (hence the name tufted folliculitis). Unfortunately, the course of this form of folliculitis is chronic-relapsing and tends to evolve into a sort of scarring alopecia.
In truth, inserting tufted folliculitis among non-infectious folliculitis would not be entirely correct, since, in most cases, it appears to be secondary to a staphylococcal infection. However, it has been observed that tufted folliculitis is not exclusively related to staphylococcal infections, but can also be the consequence of other inflammatory scalp diseases which then lead to scarring alopecia.
Given the uncertainty of the triggering cause, the treatment of this form of folliculitis is quite difficult and often disappointing. However, in case the presence of an infection with Staphylococcus aureus in progress, the therapy that is usually undertaken is the same as described for folliculitis decalvant.
Keloid folliculitis – also known as keloid acne of the neck – is a form of folliculitis found in males with curly hair. It is characterized by the formation of papules, pustules and crusts behind the neck (nape) which then lead to the formation of keloid scars (from which the disorder takes its name).
Unfortunately, currently available therapies are not able to completely solve the problem. In some cases, laser therapy or liquid nitrogen cryotherapy may help, but these treatments may not be suitable for all patients. For this reason, the doctor will have to decide on a strictly individual basis which therapeutic strategy to adopt.
Eosinophilic folliculitis is a type of folliculitis characteristic of severely immunocompromised patients, such as those with AIDS. This form of folliculitis manifests itself with the formation of pus-rich lesions, particularly itchy, which appear mainly on the face, shoulders and forearm.
Eosinophilic folliculitis is characterized by the fact that it occurs in association with eosinophilia, that is, in association with an increase in the number of eosinophils in the peripheral blood.
However, it should be remembered that – although it is observed with a greater incidence in patients with AIDS – eosinophilic folliculitis can also occur in infants, newborns and healthy adults. In this regard, it is therefore possible to distinguish three different forms: eosinophilic folliculitis in the course of AIDS, eosinophilic folliculitis in infants and eosinophilic folliculitis in adults (in health).
As you can easily guess from its very name, in this case it is not a real folliculitis, since the pimples that form do not contain pus. In reality, pseudofolliculitis is nothing more than the consequence of ingrown hairs. This type of folliculitis, which is common in people with curly hair and African-Americans, can also cause scarring on the skin. One of the best known forms, certainly, is the one that occurs in men at the level of the beard and is commonly referred to as beard pseudofolliculitis, or irritative shaving folliculitis.