Acne is primarily caused by overactive sebaceous glands and the bacterium Propionibacterium acnes, leading to blocked pores and inflammation. The condition affects a majority of teenagers and can persist into adulthood, with symptoms including greasy skin, blackheads, and pustules. Treatment options range from over-the-counter remedies to prescription medications, with the goal of controlling symptoms as acne cannot be fully cured.

1. What is the causative agent of acne?
There are several waysacne canbe caused.Acne isblockedpores,butcanbe causedby hyperactive
pores,a buildupof deadskincellsor evenbythe bacteriumPropionibacterium acnes;alotof acne
creamscontainan antibioticthatkillsthe bacteriacausingthe spots.
Propionibacterium acnes
Taxonomy: Kingdom: Bacteria; Phylum: Actinobacteria; Class: Actinomycetales; Order:
propionibacteriaceae; Family: propionibacterium; Propionibacterium acnes
Propionibacterium acnes are members of the normal microbiota that inhabit the skin (Tortora
617). Because they are of normal microbiota, this bacteria is generally nonpathogenic, but can
cause the condition acne vulagaris. These bacteria are Gram-positve, anaerobic and non-spore
forming (Propionibacterium). Even though Propionibacterium are usually obligate anaerobes,
there are a few strains that are aerotolerant (Propionibacterium causes the skin disorder, "acne").
Propionibacterium can be rod-shaped or branched; and, can be morphologically single, in pairs,
or in groups (Propionibacterium). P. acnes is indole-positive, meaning it has the ability to
convert the amino acid known as tryptophan into indole (Propionibacterium). This bacterium is
also able to produce catalase and nitrate. Propionibacterium are pleomorphic which means the
bacteria can take on a variety of different shapes (Propionibacterium). Another feature of this
bacterium is that it is diptheroid-like (Propionibacterium). This means that Propionibacterium
resemble actual diptheria bacteria in some functions such as grouping together on the skin
causing local infection, but does not produce the diptheria toxin, like the actual diptheroid
bacteria Corynebacterium diptheria (eMedexpert).
Propionibacterium acnes causes acne vulgaris by releasing lipase enzymes to digest sebum
(Acne). The free fatty acids that are formed from digestion combine with bacterial antigens and
stimulate an inflammatory response at the hair follicle (Acne).
Propionibacterium acnes produce propionic acid (Tortora 615). This enables the bacteria to keep

2. a low pH between three to five on the skin (Tortora 615). The bacteria is also able to produce
acetic and lactic acid from glucose (Tortora 615).
Acne
Published by Bupa's health information team, September 2008.
This factsheet is for people who have acne, or who would like information about it.
Acne is a skin condition that causes spots. Acne usually affects the skin of the face, back, neck,
chest and arms and the severity of the condition can vary.
 Aboutacne
 Symptomsof acne
 Complicationsof acne
 Causesof acne
 Diagnosisof acne
 Treatmentforacne
 Livingwithacne
 Questionsand answers
 RelatedBupaproductsand services
 Furtherinformation
 Sources
About acne
About 80 percent of teenagers are affected by acne between the ages of 13 and 17. However,
about five percent of women and one percent of men aged 25 to 40 continue to get or develop
acne (late-onset acne). Rarely, new-born infants develop acne from three to 24 months of age.
The processes that cause acne are exactly the same in people with all skin colours but the impact
of acne can be worse if you have darker skin.
Symptoms of acne
Acne typically causes one or more of the following:
 greasyskin
 blackheads(opencomedones)
 whiteheads(closedcomedones)
 redor yellowspots(pustules)
 deepinflamedlesions(nodulesandcysts)
 scars

3. Complications of acne
There are a number of things that can make your acne worse. These include the following.
 If you pickand squeeze the spots,itmaycause furtherinflammationandscarring.
 Excessive productionof male hormonesmaycause acne.Forexample,testosteronefrom
conditionssuchaspolycysticovarysyndrome.
 Some contraceptive pillsmaymake acne worse.Thisisdue to the type of progestogenhormone
insome pills.However,some othertypesof contraceptive pillscanimprove acne (see
Treatments).AskyourGPfor advice aboutwhichcontraceptive pilltotake.
 Some cosmeticproductssuchas moisturiserscanmake acne worse if theyare greasy.
 Some medicinescanmake acne worse.These include some epilepsymedicinesandsteroid
creamsand ointmentsthatare usedfor eczema.Don'tstopa prescribedmedicineif yoususpect
it's makingyouracne worse,buttell yourGP. He or she may be able to recommendan
alternative medicine.
 Steroidscancause acne as a side-effect.
Causes of acne
Acne is caused by overactivity of the sebaceous glands that secrete oily substances on to your
skin.
The surface of your skin has lots of small sebaceous glands just below the surface. These glands
make sebum (a natural oil) that keeps the skin smooth and supple.
Tiny pores (holes in the skin) allow the sebum to come to the surface of your skin. Hairs also
grow through these pores.
The sebaceous glands of people with acne are especially sensitive to normal blood levels of a
hormone called testosterone, found naturally in both men and women.
If you are prone to acne, testosterone triggers the sebaceous glands to produce excess sebum. At
the same time, the dead skin cells lining the openings of the hair follicles (the tubes that hold the
hair) aren't shed properly and clog up the follicles.
The combination of these two effects causes a build-up of oil in your hair follicles. This causes
blackheads and whiteheads to form.
For some people, their acne doesn't progress beyond this stage.
However, in other people the build-up of oil in the hair follicles creates an ideal environment for
a bacterium called Propionibacterium acnes to grow.
These bacteria usually live harmlessly on your skin but when the conditions are right, they grow.
They feed off the sebum and produce substances that cause an immune response. This inflames
the skin and creates the redness associated with spots.

4. In more severe inflammatory acne, cysts develop beneath the skin's surface. If these cysts
rupture, the infection can spread. This can result in scars.
Contrary to popular belief, acne isn't caused by diet or hygiene. However, acne can be hereditary.
Acne isn't infectious, so you can't catch it.
The skin
Diagnosis of acne
Your GP will ask about your symptoms and examine you. He or she may also ask you about
your medical history.
Acne is easily recognised by the appearance of the spots and by their distribution on the body.
There are several types of acne and your GP will be able to tell you which type you have after
examining your skin.
Treatment for acne
There is a range of treatment options to help treat acne. As acne can't be cured, treatments aim to
control the symptoms by:
 preventingnew spotsforming
 improvingthose alreadypresent
 preventingscarring
Your GP will usually assess your treatment after six weeks and, if beneficial, treatment will
continue for four to six months.

5. Self-help
It's important to keep spot-prone areas clean, so wash the affected area twice a day with an
unperfumed cleanser. The skin needs a certain amount of oil to maintain its natural condition, so
it's best to use gentle soaps and not to scrub your skin too hard when washing.
Medicines
There are a number of over-the-counter remedies available from pharmacies to treat mild acne.
These usually contain antibacterial agents such as benzoyl peroxide (eg Oxy and Clearasil Max).
As well as its antibacterial effects, benzoyl peroxide can dry out the skin and encourage it to shed
the surface layer of dead skin. Together, these effects make it harder for pores to become blocked
and for infection to develop.
Benzoyl peroxide can cause redness and peeling, especially to start with. This tends to settle
down if you reduce the number of times you use it. You can then build up your use gradually.
Home treatments for acne won't work immediately. It can take weeks, sometimes months, for
significant effects to be noticeable. If home treatments haven't worked after two months, or you
have severe acne, you should visit your GP.
Your GP may start your treatment by prescribing a preparation containing benzoyl peroxide. If
this doesn't work, or if you have more severe acne, there are a range of other treatment options.
These come as creams or lotions that your can rub on to your skin, or as tablets.
Creams and lotions
There are several creams and lotions you may be prescribed, including those listed below.
 Azelaicacid(Skinoren) isanalternative tobenzoyl peroxide andmaynotmake your skinas sore
as benzoyl peroxide.
 Retinoids(egAdapalene) are medicinesbasedonvitaminA,whichyoucanrubintoyour skin
daily.Theyworkbyencouragingthe outerlayerof skinto flake off.
 An antibioticlotion,suchasclindamycin(egDalacinT) orerythromycin(egStiemycin),applied
to yourskincan be usedto control the P. acnesbacteria.Youwill needtocontinue this
treatmentforat leastsix months.
 Creamsand lotionsthat combine anantimicrobial withotheracne medicationare alsoavailable
(egQuinoderm).
Creams and lotions are only effective where and when they are applied so you should apply these
daily to all areas of your skin that are prone to acne.
Tablets
There are several oral treatments you may be prescribed.

6. Antibiotics, such as tetracycline, can be prescribed for inflammatory acne. You should take these
daily for around three months, although it might take four to six months for you to see the
benefits. The success of this treatment can be limited because the strains of bacteria are often
resistant to the common antibiotics. Antibiotics don't prevent pores from becoming blocked so
treatment to prevent blackheads, such as benzoyl peroxide, is often also prescribed at the same
time.
Some types of oral contraceptive tablets help women who have acne. A combination of the usual
contraceptive pill hormone called ethinylestradiol with cyproterone acetate (eg Dianette)
suppresses male hormone activity. This drug has been shown to reduce sebum production so is
often used in women with acne.
Isotretinoin (eg Roaccutane) is a medicine known as an oral retinoid, which is also available as a
cream (see Creams and lotions). Isotretinoin works by drying up oily secretions. It tends to be
prescribed to people with severe forms of acne that have proved resistant to other treatments.
There are a number of serious side-effects of this drug, such as liver disorders and depression.
You shouldn't take isotretinoin if you're pregnant, as it's very dangerous to an unborn baby. For
safety reasons, isotretinoin is only prescribed under the supervision of a dermatologist (a doctor
specialising in skin conditions).
Living with acne
Acne not only causes physical symptoms but may make you feel anxious or depressed as well.
You should start treatment as early as possible to reduce the risk of scarring and follow your
doctor's advice about treatment.
With good management and appropriate treatment, most people are able to control their acne.