Skin is the largest organ in the human body and it makes up as much as 15% of its total weight. It represents a protective barrier that acts in two directions: on one hand, it prevents loss of water and electrolytes from the organism and on the other, it protects it from entry of harmful substances. Further, skin has an important role as part of the general immune system. Morphologically speaking, the skin is composed of three layers – the epidermis, dermis and subcutis, with the epidermis and dermis playing a part in the development of acne.
The epidermis is the surface layer composed of keratinocyte cells. Underneath the epidermis the dermis is found: a thick layer of skin consisting mainly of collagen connective tissue. The dermis also includes blood and lymph vessels, nerve endings, sebaceous and sweat glands and hair roots.
The follicle (hair canal) is the place where desquamation or shedding of dead skin cells constantly takes place, and it also houses the sebaceous gland that secretes sebum to the surface of the skin. More precisely, sebum is mixed with shed cells in the hair canal and, in the ideal case, together they are discharged to the surface of the skin. When this canal is clogged, the ideal conditions for the appearance of acne develop. Excess production of sebum complicates this process, and it’s most often produced excessively when androgen hormones are active, which is especially pronounced in adolescence (in both genders), and in the second (luteal) phase of the cycle of adult women when oestrogen levels fall.
How does acne develop?
Androgen hormones have a manifold role in the development of acne. Acne do not appear in individuals who have a genetic flaw in the functioning of androgen receptors, that is, they appear much more often and intensively in individuals who have higher levels of androgen hormones such as testosterone, dihydrotestosterone (DHT) and androstenedione, which are easily detected by blood tests. Still, sometimes individuals even with normal serum levels of androgen hormones have acne and that is due to a high level of sensitivity of androgen receptors in the skin which is genetically conditioned.
Androgen hormones are produced in several places in the organism: in the adrenal glands, testicles and ovaries, as well as outside of glands: in the liver, skin and fatty tissue. The development and operation of the sebaceous glands is directly controlled by the androgen hormone which begins to be produced in puberty, which explains why children never suffer from acne (with the exception of babies who develop childhood acne due to androgen hormones from their mother’s milk).
Androgen hormones are also stimulated by increased stress. In women, lower quantities of androgens are produced, so a sudden and abrupt raise in androgen levels due to stressful life events may significantly worsen acne. A study conducted on a sample of 4 000 women with acne, aged between 25 and 40, found that stress was the cause of acne in 50% of the cases.
In addition to the higher amounts of sebum produced, acne development is also linked to changes in the composition of certain lipid components in sebum. Sebum is made up of several ingredients: polar lipids, neutral lipids, wax esters, squalenes and triglycerides. Under the influence of bacteria, triglycerides break down into free fatty acids which have a very irritating effect on the skin. Locally reduced production of essential fatty acids (like linoleic acid) is also one of the key factors in acne development.
Apart from the effect of androgen hormones on the amount of sebum secreted and the reduced quality of sebum, which in individuals suffering from acne is stickier and waxier due to linoleic acid deficiency, the disrupted functioning of the already mentioned hair canal also plays a role in acne pathogenesis. This disruption leads to hyperkeratosis of the hair canal. Cells that are shed and need to be discharged from the hair canal along with sebum, remain there and form a comedone or “plug” which prevents further sebum discharge.
Ultimately this creates the perfect conditions for propagation of the propionibacterium acnes (p.acnes) bacteria which feeds on sebum in clogged pores in which oxygen is lacking. P.acnes secretes enzymes that help break down triglycerides into free fatty acids which trigger an inflammatory effect. Acne is developed as the immunological response to the pro-inflammatory action of the p.acnes bacteria.
In short, acne are developed due to interaction of the following factors: the effects of androgen enzyme pathways; disruption of keratinisation along with a deficit in linoleic acid in the sebum; effect of inflammation mediators released by the p.acnes bacteria and due to genetic predisposition.
From comedone to acne
Comedones are a non-inflammatory form of acne, and can be classified by type into black and white comedones.Black comedones or blackheads must also be differentiated from normal enlarged pores that freely perform their function of sebum discharge. Blackheads are usually located on the T-zone and can be told apart from regular enlarged pores by their size, much darker colour and localisation. If it seems to you that every one of the pores on your face is morphologically a blackhead, it’s much more probable that enlarged pores are in question and that they need to be treated in a way that will avoid clogging.
Real blackheads are composed of oxidised keratin and accumulated melanin pigment from discharged cells and they seldom turn into inflammations. Closed comedones are, on the other hand, a time bomb. A closed comedone is located deeper in the follicle and it appears in the form of a skin-coloured papule (0.1 to 3mm in size). Discharge of sebum to the surface of the skin is reduced to the minimum which is one of the preconditions for propagation of the p.acnes bacteria, and in turn, the development of acne. Depending on the depth of the follicular canal in which the inflammation is located, milder or more serious forms of acne will develop.
In the case of especially deep acne, a scar will form, sometimes even regardless of whether the acne was “picked at” in an attempt to rid it of its contents. If only the epidermis and surface dermis have been damaged, a reddish mark will be left on the skin and will remain from several weeks to as long as several years. This is post-inflammation erythema. While there is no cosmetic solution for already created scars apart from very mild improvement of the skin’s texture, a post-inflammation erythema is possible to be treated by adequate skin care, taking into account the fact that this is an inflammation that is attempting to heal itself and that applying irritating ingredients that may be found in cosmetics can only make this process harder or longer.
How to treat acne and comedones?
Severe forms of acne are not treated with skin care products but with prescription drugs and a systematic therapy plan. Mild to moderate, mostly comedonal and mild papulopustular acne are successfully treated by a well-thought-out selection of cosmetic products. There are three main requirements that a product must meet in order to be effective against acne.
First, the product must be non-occlusive and mustn’t contribute to clogging of pores. Second, the product must be non-irritating since irritation prolongs the inflammatory response of the skin, which means that it mustn’t contain conventional irritants. Third, the product must have effective active ingredients in adequate concentrations.
Although the market is saturated by numerous products promising quick results in the treatment of spots and comedones, recommended dermatological treatment of acne consists of just a couple of active components: niacinamide which shows success in treating acne in concentrations above 4%, keratolytics such as salicylic, glycolic and lactic acid that prevent retention hyperkeratosis, comedolytics from the retinoid group and benzoyl peroxide which releases oxygen that has a direct effect on the propagation of the p.acnes bacteria. Keratolytics and comedolytics also have a strong anti-aging effect and significantly retexture the skin. The potential drawback of the active ingredients mentioned is the possibility of temporary redness and irritation in the case of sensitive skin. It is also recommended that they be avoided during the sensitive period of pregnancy, which especially applies to all types of retinoids.
Although more aggressive acne treatments may give quicker results, they always come with greater risk of irritation, and irritation is one of the factors that lead to repeated inflammation. In breaking this vicious cycle, Skintegra believes in taking a moderate approach and using a constant skin care routine. Skin that is treated against acne and comedones must never be painful, dried out or flaking since a healthy hydrolipidic barrier is extremely important in the process of treating inflammations. Problematic skin also mustn’t be burdened by excess ingredients that don’t contribute to acne treatment. That means that in the treatment of acne-prone skin one must avoid known comedogenic components, perfume components, high concentrations of denaturated alcohol and ethanol, synthetic dyes, essential oils such as menthol and eucalyptus (apart from tea tree oil that has a proven anti-bacterial effect), oils that easily turn rancid (oxidise) and irritate the skin, SLS and SLES, known allergens such as linalool, geraniol, eugenol, camphor) as well as photo-toxic ingredients in the daytime routine (citrus components).