Acne causes & Acne vulgaris etiologic factors


Treating acne breakouts require thorough understanding of its pathogenesis [1], etiological factors [2] and manifestations. Acne is common among teenagers (prevalence of 80% in the majority of countries worldwide) [3], yet it could affect people over 20. Acne causes has been researched extensively and multitude of factors have been identifies in etiology. Although acne is most prevalent among teen-aged males, most can expect spontaneous treatment by age 25.

Adult females may continue to experience acne into the adult years, sometimes beyond the age of 40. It is more common in males, 29.9% in men versus 23.7 in females [4]. Problem skin ( skin implicated with acne ) characterizes by clogged enlarged pores, excess production of sebum and fatty inclusions , abnormal bacterial function and production of inflammation in acne lesions.

mtorc1 signals upregulation of lipogenesis and implicates in acne causes

mtorc1 signals upregulation of lipogenesis and implicates in acne causes

Fibroblast growth factor receptor signaling

Fibroblasts growth factor receptor (FGFR), a family of tyrosine kinase receptros, signaling appear to be another mechanism in orchestrating follicular hyperkeratinization and sebocytes proliferation and contribute to developement of acne vulgaris. This concept envision the idea that FGFR signaling may manipulate known mechanisms by which anti acne treatments operate. In line with these studies, it has been proposed that free radicals generated by benzoyl peroxide downregulates signal transduction by fibroblast growth factor receptors and leads to dwindled sebocyte proliferation and sebum production.

Fibroblast growth factor receptor signaling in pathogenesis of acne vulgaris

Fibroblast growth factor receptor signaling in pathogenesis of acne vulgaris, decreased sebocytes proliferation and sebum production

Role of different factors in development of acne

Acne is a multi factorial disease. Genetic [5], racial [6], hormonal, dietary and environmental factors have been implicated and broadly recognized as acne causes, while it is clear that its psychological implications may be severe. Although the role of heredity in acne has not been clearly denied, there is a great tendency toward more serious involvement if one or both parents had severe acne during their youth .

Hormonal factors and acne

Hormones, androgens [7], are well known amid acne causes and pathogenesis. Sebaceous glands ( part of sebaceous follicles ) are extremely sensitive to androgenic stimulation, and their enlargement usually precedes other obvious signs of puberty even before any sign of acne [8]. Terminal sebaceous differentiation is assisted by peroxisome proliferator-activated receptor ligands [9]. Relationship between sebum out put and testosterone as a representative plasma androgen.[9].

Sebocytes are under endocrine control and so it is not surprising that sebum production varies with age and sex [10]. Increase in sebum production is associated with increase in free fatty acids rather than an increase in essential fatty acids. Males have a significantly greater sebum production than females. The sebum production continues to increase after puberty, reaching a peak in both sexes between 30 and 40 years, and thereafter there is a gradual decline. Sebum appears to be central amid factors contended with by acne causes.

Androgens affect differentiation of pilosebaceous unit

Solid lines indicate the effects of androgen, dashed lines indicate the effects of anti-androgens. In balding scalp (bracketed area) terminal hairs not previously dependent of androgen regress to vellus hairs under the influence of androgen [11].

It is evident that the sebaceous gland is an androgen target organ and any measure pharmacologically to control androgens is a logical approach to treatment of acne. Hormonal therapy remains an important part of the arsenal of acne treatments available to the clinician [12].

Emotional factors and acne

As with any disease whose course is prolonged and capricious, the importance of psychological factors in treatment of breakouts has been repeatedly stressed and should be seriously taken into account when using treatments [13]. Patients with cysts frequently report being self conscious, anxious and socially isolated. Not only the psychological status is influenced in subjects with stress but also their sympathoadrenal system [14]. There seems to be no doubt that stressful situations such as final examinations regularly explained as what causes acne exacerbations in patients. This is probably the result of increased glucocorticoid secretion by the adrenal glands that seem to potentiate the effect of androgens.

One more evidence suggesting role of stress in acne pathogenesis is studies on substance P. Substance P, which can be elicited by stress and expressed in the nerve endings at the vicinity of healthy-looking glands, promoted the development of cytoplasmic organells in sebaceous cells, induce significant inncreases in the area of sebaceous gland and increased the size of individual sebaceous cells, all of which suggests that substance P promotes both the proliferation a and the differentiation of sebaceouls glands [15]. Attention should be paid to psychosomatic aspects especially if depressive-anxious disorders are suspected, particularly with evidence of suicidal tendencies, body dysmorphic disorders or also in disrupted compliance [16].

Environmental factors and acne

Role of various lights on acne vulgaris

Environmental factors also play a major role in determining types, severity and extent of acne and affect topical treatments. In most cases the manifestations are worse in winter and improves during the summer, suggesting a salutary effect of sunlight [17]. Sun-bathing may be beneficial for psychological reason and may produce euphoric effects. Nonetheless, some studies recognize sun exposure and air pollution as aggravating by oxidative stress causing dysseborrhea and comedone formation illuminating role of proper suncare in acne patients. Some forms of light therapy were of short-term benefit. However, very few trials have been conducted to examine long-term benefit of this treatment [18]. Photodynamic therapy (PDT) appears to be a useful therapeutic option for acne patients who are recalcitrant to standard treatments and poor candidates for systemic retinoids [19].

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