Pathogenesis & Pathology
There are many factors contributing in acne pathogenesis.
The epidermis is the outer layer of the skin and its role is important, acting as a “barrier” to protect the body from the penetration of microbes and various toxins. There are many microorganisms that are born, live and die on human skin and therefore it is considered a complex ecosystem.
Despite its protective role, there are certain microbes that turn into opportunistic pathogens under certain conditions, causing skin disorders such as acne. At the same time, the aetiology and pathogenesis of acne are not yet clearly understood, although it is a very common skin disorder.
The main pathogenesis involves hormonal imbalance, abnormal keratinisation and bacterial infection (see Figure). Moreover, hereditary factors, the patient’s age, diet, stress and extrinsic factors such as nutrition as well as psychological influences are complicatedly associated with acne’s onset.
- Hormonal Imbalance
Hormonal Imbalance occurs when normal levels and production of hormones in the endocrine system, or their ratio to other hormones is disrupted.
- Follicular hyperkeratinisation
Follicular hyperkeratinisation is essential in the pathogenesis of acne and the main target of retinoid activity. It occurs when the cells of the follicle become cohesive and do not shed normally on the skin’s surface. The outcome is microcomedone and lesions characteristic of acne.
- Bacterial infection
- P. acnes (Propionibacterium acnes) is an anaerobic organism which proliferates in this environment of sebum and follicular cells, breaks down triglycerides in the sebum-producing free fatty acids that destroy the hair follicles leading to inflammation, especially when there is infestation by the Demodex folliculorum mite.
- Staphylococcus aureus holds the most prominent position in the skin microbiota. It plays a particularly important role as a pathogen in many skin infections, such as folliculitis and impetigo, while it has been demonstrated that it co-exists with other microbes in acne lesions.Several studies indicate that Staphylococcus aureus can sometimes affect the onset of acne vulgaris. Furthermore, Staphylococcus aureus develops resistance to both topically applied antibiotics and systemically administered antibiotics, i.e. orally administered medication.
Frequent administration of antibiotics for the management of moderate or severe acne seems to lead to changes in the normal human microbial flora. For decades, there have been severe concerns regarding the increased resistance of Staphylococcus aureus to antibiotics.
According to a published study in the Journal of the American Academy of Dermatology and Venereology, the prolonged use of antibiotics by patients with acne leads to Staphylococcus aureus resistance to them compared to patients without acne. Similar findings concluded that there is a higher incidence and greater resistance to Staphylococcus in the oropharynx (the part of the pharynx that lies between the soft palate and the hyoid bone) of people with acne compared to people without. This indicates that the said bacterium interacts with acne and suggests that acne could be mainly caused by the presence of this particular bacterium.
Therefore, it is of utmost importance to examine the bacterial flora and the sensitivity of isolated strains towards antibiotics among acne patients. This is even more significant in cases of severe acne or among people not responding to treatment.
This is why at IQ Intensive Quality Dermatology Clinics, direct testing and cultivation for S. aureus is performed, as well as antibiotic sensitivity testing (antibiogram), in order to verify the presence of staphylococcus. According to the results of the laboratory tests and the clinical examination, the appropriate therapeutic regimen is specified individually for each patient with acne.
- Genetic Factors
There are several studies suggesting that genetic factors influence an individual’s predisposition to acne. One, conducted in Germany demonstrated that the 45% of schoolboys with acne, all had one or both of their parents who had also suffered from the skin condition against 8% of parents who had not.
In parallel, there are studies which have presented evidence that confirm a very high similarity between identical twins in comparison to fraternal twins. Also, patients with persistent acne have a strong family history of persistent acne, in contrast to patients with adolescent acne. Likewise, a correlation between neonatal acne and familial hyperandrogenism has been suggested.
- Environmental – External factors
- Psychological and Social Effects of Acne
Acne can be influenced to a certain extent by various environmental and external factors:
In many cases, sweets and chocolates have been implicated, but there is no sufficient scientific data to prove a causal relationship between diet and acne. In a review, conducted by Mahmood and Bowe focusing on the relationship between diet and acne, the researchers concluded that carbohydrates’ intake may influence acne. More specifically, many studies suggest that a diet with low glycemic load helps in improving acne. The researchers note that the exact mechanism underlying this relationship has not been confirmed yet, but according to the epidemiological data, patients with acne should be informed about the potential benefits of diet.
In certain cases, a person’s profession may influence or worsen acne. For instance, working in a really dry or warm environment or with chlorinated aromatic agents used in industry as well as with other chemical agents that cause or promote pore clogging.
According to one study, (although not confirmed) researchers have indicated that there is a linear relationship between acne prevalence and the number of cigarettes smoked daily, possibly supported by the overall living conditions of smokers.
Psychological and social effects of acne constitute a particularly significant issue, especially since acne affects a large percentage of adolescents in a period that is critical for personality and interpersonal relationships development. Acne may be a reason a person is not accepted by his/her friends and peers because appearance is an issue that concerns them. The same is also true for acne sufferers, who may lack self-esteem as a result of their acne.
Stress has been found as a factor that could influence the onset of acne or worsen existing acne. In a study that was conducted in Canada with the participation of approximately 500 patients with the condition, it was found that even mild acne can cause low self-esteem, depression and reduce self-confidence, as well as a negative body image. At the same time, acne can lead to a feeling of shame and psychological stress, while it may also be linked to social phobia. Apart from that, patients with adult acne may be discriminated both at a personal and at a professional level.