Acne Causes : Causes of Acne in Adults

The underlying acne causes involve a series of five main factors which result in dysregulation of the pilo-sebaceous unit. The dysfunction of the pilo-sebaceous unit may occur in varying severity and is manifested accordingly by the acne lesions. This gives an idea of what is acne vulgaris and what are the causes of acne in adults. The factors involved in pathogenesis of acne vulgaris can be categorized as below.

Hormonal Factor : There is a close relation between acne vulgaris and hormonal imbalance. The onset of puberty results in high production of hormone androgen from the testes, ovaries and adrenal glands. They are the main stimulants of sebum excretion and also the most common cause of acne in individuals of 15-20 years age group. Elevated androgenicity is a normal physiological condition due to puberty.

But sometimes high androgen level may also occur due to some disease conditions like Polycystic Ovarian Syndrome, Congenital Adrenal Hyperplasia,Cushing Syndrome and Androgen Secreting Tumors. Some other hormones like thyroid hormone and growth hormone also cause mild stimulation of the sebaceous glands.

During breakouts of acne vulgaris the sebaceous glands react excessively to the otherwise normal levels of these influencing hormones. This demonstrates the acne vulgaris-endocrine system-hormones intricate relation in acne formation.It has been found that those who have been castrated before puberty never develop acne.

Physiological Factor : High amount of sebum is produced by the sebaceous glands due to increased androgen level in the body. The excess sebum gets deposited on the upper part of the hair follicle. This results in the evolution of acne which may appear as either a closed comedo or whitehead and if the orifice of the pore dilates it forms an open comedo or blackhead.

Commonly the rate of sebum secretion is increased during the teenage period due to increased androgen being produced by the body.But this is not the only cause of acne since high sebum excretion also occurs in certain other conditions like Parkinson’s disease and Acromegaly but these patients do not develop acne.

De-saturation of fatty acids in sebum may lead to the development of acne lesions.In acne prone people,the sebum is found to contain specific enzymes known as Lipoperoxidases. Lipoperoxidases combined with some quality changes in the sebum cause alteration of keratinocyte differentiation and induce Interleukin-1 secretion which lead to follicular hyper-keratinization.

Cellular Factor : Impaired desquamation and proliferation of keratinocytes near  the orifice of the follicle pore result in formation of a hyperkeratotic plug. This develops within the follicular canal and results in formation of a micro-comedo.This cellular obstruction is a vital aspect in pathophysiology of acne vulgaris.

A local inflammatory process develops as neutrophils and other host immune cells accumulate.In patients suffering from acne vulgaris the skin is found to secrete certain inflammatory chemicals like Interleukin-1, Interleukin-8 and Tumor Necrosis-Alpha. Papules form and after the pilosebaceous follicle ruptures into the surrounding dermis it forms more severe pustules (filled with pus) and cystic lesions may form.

Skin Infection : The acne bacteria Propionibacterium Acne plays a pathological role in acne breakouts. Propionibacterium Acne colonizes the pilosebaceous ducts,breaks down triglycerides releasing free fatty acids. This gram positive anaerobic bacteria thrives in the sebum rich growth medium which is important for its survival.

Although Propionibacterium acne is a normal component of skin flora it is found in higher concentration in patients suffering from acne.It naturally produces some chemical substances known as Porphyrins (Coproporphyrin III) which is the target of radiation therapy of treatment.

It also secretes enzymes known as lipases which break down lipids and results in formation of pro-inflammatory free fatty acids which give rise to comedones.This bacteria is found to survive in an anaerobic environment with lipids as a nutrient source.

Heredity : Acne is found to be familial in some cases.Family history of acne is found  in about 45%-50%of patients suffering from acne with high chance in mono-zygotic twins rather than di-zygotic twins.It is found that the presence of a  first degree relative having acne increases the likelihood of developing acne by four folds.

Therefore,acne and genetics share an important relation.In individuals having a positive family history of acne certain changes in the normal physiology and sensitivity of skin are found to be present. This abnormalities make them more prone to develop acne despite having normal hormone level in the body and presence of favorable environmental conditions.

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