Acne Vulgaris: Pathogenesis, Causes, Treatment

Acne is a skin condition that is seen predominantly in adolescents. They can also be seen in adults due to hormonal changes referred to as Adult acne.

Acne is a chronic inflammatory disease of the pilosebaceous filaments that is typically seen on the face, neck, upper arms and upper body as well.

They can be inflammatory or noninflammatory types

Non-inflammatory

These include blackheads and whiteheads which are also called comedones. When the follicles get clogged and are exposed to the environment it turns black which is also known as open comedones or blackheads. When the comedones are closed they are referred to as whiteheads.

Inflammatory

These include various types such as papules, pustules, nodules, cysts or nodulocystic acne.

Inflammatory acne presents with redness swelling of the surrounding area and are painful in nature.

What are sebaceous glands?

These are holocrine glands which occur in conjunction with the hair follicle unit also known as the pilosebaceous unit. Sebaceous glands are present throughout the body except for the palms and soles. They are responsible for the production of sebum that is rich in squalene fatty acids, cholesterol esters, wax and wax esters. The amount of secretion of these fatty acids from the glands determines the skin type as normal, dry, combination, oily.

What is the pathogenesis behind the formation of acne?

There are multiple factors that involve the occurrence of acne on the skin.

Hyperkeratinization of the follicle-

This leads to thickening and formation of dead skin layers which causes the follicles to get clogged resulting in excess oil and bacterial proliferation leading to acne formation. Keratolytic agents such as BHA and LHA are used in order to dissolve these plugs and unclog the pores.

Bacterial proliferation

Bacteria that are responsible for the formation of acne vulgaris is propionibacterium acnes.

This bacteria feeds on the oil produced by the glands and flourish in the follicles leading to inflammation and formation of acne.

Inflammation

Inflammation is the key component for the formation of acne. When something goes wrong in the body, the immune system gets activated in order to get rid of the culprit. Inflammation is the body’s immune system response to pathogens and other foreign elements. When there is inflammation it can lead to acne on the skin as well. Pro-inflammatory foods such as High glycemic foods can make the condition worse.

Excess sebum production

Too much oil produced by the glands can occlude the pores, resulting in the formation of the plugs as well. The microbial flora feeds on these oils and causes the formation of acne.

Hormonal factors

The imbalance in the hormonal levels in the body can also mess up with the system leading to hormonal acne. The various conditions that can result in hormonal acne are- androgen stimulation, insulin resistance, insulin growth factor-1, polycystic ovarian disease (PCOD) late onset congenital adrenal hyperplasia.

PCOS acne is a very common condition seen in women of various age groups. Follicular androgen stimulation due to polycystic ovarian syndrome/ polycystic ovarian disease can lead to excessive hair growth (hirsutism) and keratinisation of the follicle (comedone formation).

What are the other causes of acne?

Drug induced acne

There can be acne formation due to intake of certain drugs. This condition is called acneiform eruptions. Drugs responsible for this condition are topical/systemic steroids anticonvulsants (carbamazepine, phenytoin), anabolic steroids (danazol, stanozolol).

Acne conglobata

This is a serious nodulocystic disease in which multiple nodulocystic acne are combined together forming interconnection sinuses leading to extensive scarring on the skin. Treatment of this condition is necessary at an early stage.

Acne fulminans

This is also known as acute febrile ulcerative acne. Multiple nodulocystic acne is seen on the patient along with ulceration and crust formation. The patient may also appear with fever and malaise. These cysts are extremely painful, inflamed and are covered with hemorrhagic crusts. The condition might be triggered by oral isotretinoin and anabolic steroids.

Fungal acne

Also known as malassezia folliculitis caused by disruption in the normal microbial flora of the body. This causes the overgrowth of yeast and clogging of pores. The yeast feeds on the oil produced by the glands causing monomorphic bumps on the skin as well. 

Food associated acne

High glycemic foods are inflammatory in nature which can lead to the formation of advanced end stage glycation products that harms the skin, leads to skin aging and also acne. Milk and milk based products can also lead to the formation of acne.

What is the treatment?

Comedonal acne

The most commonly prescribed medications for primarily comedonal acne are topical retinoids.

Adapalene and tretinoin are the drug of choice.

These have keratolytic action that helps in dissolving the keratin plugs wrestling in unclogging the pores.

Papular acne

When acne is most commonly present in the form of papules topical retinoids are given along with conjunction of topical antibiotics.

The retinoids have a keratolytic effect and antibiotics help in killing the bacteria. Most commonly used topical antibiotics are- clindamycin, clarithromycin, nadifloxacin, dapsone.

Pustular acne

Topical retinoids, topical antibiotics are combined with oral antibiotics as well.

Oral antibiotics that work against pustular acne are- doxycycline, minocycline, and azithromycin.

Another effective treatment is to add benzoyl peroxide which is a powerful topical agen with mild comedolytic action. Benzoyl peroxide works effectively and is the drug of choice in drug resistant acne.

Nodular/cystic/nodular-cystic acne

Oral isotretinoin is given in these cases. This is also the drug of choice in patients who are non-responsive to antibiotics. 

Intralesional steroids can also be given into the cyst to reduce inflammation.

Side effects of oral isotretinoin are- dryness, increased lipids, hepatitis, teratogenic(should not be given in pregnant females)

Hormonal acne

For maintaining the hormonal levels in the body oral contraceptive pills are given.

Another drug includes spironolactone for treatment of hormonal acne.

Acne in pregnancy

Topical benzoyl peroxide

Topical erythromycin

Topical azelaic acid

Note- always consult with your dermatologist and gynaecologist for treatment of acne during pregnancy.

Lasers-

Intense pulse light therapy and photodynamic therapy destroys the propionibacterium acnes by targeting porphyrins produced by these bacteria.

Chemical peels-

Glycolic acid peels, AHA and BHA combined peels work great together for exfoliating the skin and removing keratin plugs.

Hope you found this article helpful.

Note- Always consult your dermatologist before starting any Oral / Topical treatment.

Disclaimer- This post is for information purposes only. It is not meant to diagnose or treat any medical condition. 

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