White wavy lines texture on a surface

Redness

Definition: A physiological condition in which the face, or other parts of the body, take on a more or less intense red colour. This phenomenon indicates a significant influx of blood, when the blood capillaries that irrigate the skin dilate excessively in the dermis. This is generally observed in hypersensitive skin, due to an impaired skin barrier and hyper-reactivity of sensory fibres, whereas they may not necessarily have manifested on normal skin. Redness can appear in localised areas, primarily affecting the central part of the face (cheeks, nose, forehead and chin), or spread across the entire face in the most extreme cases. Depending on the skin's condition, they can be temporary and subside within a few minutes, or persist for hours, days or even weeks. Even though they are more commonly observed in people with fair skin, all skin types can be affected. In some cases, redness can be accompanied by other symptoms (spots, itching, sensation of heat, etc...).
Internal and external causes: Genetic predisposition (individuals with so-called "vasoreactive" skin), age, intake of certain medications, strong emotion, pollution, skin trauma, consumption of spicy foods, stress, allergic reactions, physical activity, exposure to extreme temperatures, use of overly aggressive skincare products, UV radiation, exposure to certain chemicals, alcohol consumption, hormonal states (menopause), and certain skin conditions (eczema, dermatomyositis, seborrheic dermatitis, rosacea, urticaria).
How to reduce or eliminate: Using cosmetics that contain active ingredients with healing, soothing, anti-inflammatory, and vasoconstrictive properties (beta-glucan, hemp oil, azelaic acid, niacinamide, Centella asiatica, allantoin, bisabolol, calendula macerate, etc...); opting for skincare products that strengthen the skin barrier, providing protection against external aggressions; diminishing/camouflaging redness with a green-tinted concealer; considering aesthetic treatments (vascular laser, Flash lamps, Kleresca photo-modulation); consulting a dermatologist if the redness persists (prescription of topical or oral treatments).
Preventative steps to take: Avoid hot baths; steer clear of saunas and steam rooms; limit alcohol and spicy foods; protect your skin from climate changes; avoid grainy exfoliators; be gentler in your movements; refrain from applying irritating cosmetic products; use sun protection; daily free your skin from makeup and impurities with a cleansing balm/oil rich in vegetable oils; provide your skin with an additional source of hydration daily with a moisturising cream; avoid "rubbing" the face during cleansing.