The various forms of rosacea.

Rosacea manifests itself through widespread and diffuse redness on the face , particularly on the forehead, nose, cheeks, and chin, due to the high vascularisation of these areas. Rosacea is characterised by a significant dilation of the facial blood vessels, making them more visible, especially on lighter skin tones. These signs are often accompanied by skin hypersensitivity, hot flushes, as well as burning and tingling sensations.

Indeed, rosacea tends to progress over time. Its symptoms can notably disappear for a few weeks before suddenly returning in a more intense manner. Indeed, the face can be affected by significant swelling, deformities, or papules. In the most severe cases, rosacea affects the eyes and causes their inflammation.

The causes of this dermatological disorder are still poorly identified, however, several ongoing studies have shown that certain factors could be responsible for rosacea flare-ups. These include hereditary predisposition, parasitic colonisation, heat, sunlight, stress, or the consumption of certain spicy foods. These various elements, apart from genetics, are capable of activating certain receptors present in the epidermis, which have nociceptive and/or inflammatory roles. It has thus been shown that exposure to one or more of the aforementioned factors contributes to promoting hot flushes, redness and sensations of irritation experienced by individuals affected by rosacea.

Rosacea is the cause of various symptoms, ranging in severity. The initial manifestations of rosacea are often mild but it can subsequently develop into a more serious condition. Four subtypes of rosacea are identified.

The condition of rosacea or vascular rosacea.

This form of rosacea is quite common. The first sign of couperose is the gradual onset of diffuse redness, taking the form of patches on the face. The areas around the eyes and mouth are often spared. Initially, the redness disappears but, eventually, it becomes permanent. This is then referred to as erythrosis.

They are generally accompanied by intense hot flushes and increased skin sensitivity. In some cases, the natural peeling of the skin tends to be accentuated and it becomes drier. People suffering from rosacea often complain of burning and tingling sensations on the skin.

In the event of vascular rosacea, we also observe the emergence of small red or purplish blood vessels beneath the skin, a result of their dilation. Characteristic of this skin condition, they are referred to as telangiectasias. Occasionally, some skin swelling may also appear.

Papulopustular rosacea.

This form of rosacea typically follows couperose. It occurs due to the invasion of the parasite Demodex into the sebaceous glands. They are naturally present in the epidermis where they play a seboregulatory role. However, when more than 5 parasites per cm² of skin are observed, it is considered a colonisation.

The Demodex mites secrete proteases, enzymes involved in the breakdown of proteins, which stimulate the activity of PAR-2 receptors (Protease-Activated Receptor) that play a central role in inflammatory and nociceptive processes. This activation subsequently leads to the release of TNF-α and interleukin-1 (IL-1), inflammatory agents.

Beyond redness, hot flushes and feelings of tightness, we observe in people suffering from papulopustular rosacea the emergence of skin lesions. This condition is sometimes mistaken for acne, as it also leads to the appearance of papules, and in some cases, pustules.

Hypertrophic rosacea.

This type of rosacea is a significant complication, due to the substantial aesthetic damage it causes. Quite rare, hypertrophic rosacea is characterised by a thickening of the skin, as well as a dilation and inflammation of the nose pores, referred to as "rhinophyma". In some cases, the skin thickening is sometimes associated with papulopustules and can extend to the rest of the face.

Hypertrophic rosacea originates from an enlargement of the sebaceous glands. The causes remain somewhat unclear, but it is considered to be a strong inflammatory response triggered by the infectious agent Demodex. The nose is particularly affected, as this area contains a large proportion of the sebaceous glands on the face.

Ocular rosacea.

It is estimated that approximately 30 to 50% of rosacea cases are accompanied by an ocular condition. When it affects the eyes, this disease causes burning and itching. This eye condition is also characterised by inflammation and swelling of the eyelids. It is thought to be due to a dysfunction of its glands, the Meibomian glands.

Located at the base of the eyelids, they normally contribute to the lubrication of the eyes by secreting an oily substance. Ocular rosacea also causes a dryness of the eyes, which become red and teary. The eyes then become particularly sensitive to light. Small blood vessels dilate and become visible on the white area of the eye.

It is crucial to consult a dermatologist at the first signs of symptoms. Mild rosacea can quickly lead to complications, particularly affecting the eyes.

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