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What is Acne?


Acne refers to infection of the hair follicles and sebaceous (oil) glands by bacteria which live on the skin (Propionebacterium Acnes).  


Who gets acne?


Acne occurs at any age from puberty onwards. Contrary to popular belief, Acne is not just a teenage problem as it can occur in individuals as young as 9 and as old as 50 years.



Acne Myths


Despite what you hear, acne is not caused by chocolates, oily foods, fries, dirt or dandruff. People who get acne do not lack hygiene and acne is not contagious.



The Diet and Acne


There are many individuals who complain that their acne worsens after they eat certain types of food.  If you are such an individual, it is probably best to avoid such foods, especially before important social events.


Scientific evidence that acne is caused by dietary factors is lacking. A notable excpetion is the role of dairy products in worsening acne. This is largely due to the fact that cows are injected with hormones to increase milk productivity and to made them grow more rapidly.

How does Acne develop?


Acne is almost always hormonal. At puberty, there is an increase in the secretion of the hormone androgen. This causes increased output of sebum (oil) from the oil gland. Large volumes of oil flow out of the gland irritating the opening of the pores which thicken and become blocked. Oil is then trapped within the hair follicles. A whitehead (closed comedone) is then formed by the trapped oil. When exposed to air, the oil changes colour to a dark brown/ black resulting in the development of a blackhead (open comedone). 


Bacteria on the skin are attracted to this trapped oil the way ants are attracted to sugar. The entry of bacteria sets off an inflammatory reaction resulting in red pimples (erythematous papules). When this reaction is severe, the body's white cells attack the bacteria and pus is produced. A yellow pimple (pustule) is then seen. Several red pimples may join up to form nodules while pustules join up to form cysts.

The annoying part of untreated acne is that it heals with scars.

The development of acne is illustrated graphically below (illustrations by Dr N Raboobee):

The diet and acne
Normal hair follicle & seb gland

Normal hair follicle (left) and sebaceous gland (right) - the scenes of the crime in acne.

Screenshot 2017-05-10 20.37.49

Oil (sebum) is produced by the oil gland (right) and flows to the skin surface through the hair follicle.

Screenshot 2017-05-10 20.37.57

Excessive oil production causes irritation of the opening of the hair follicles resulting in its blockage

Screenshot 2017-05-10 20.39.20

Immune cells arrive in the hair follicle to attack the bacteria and pimple becomes red.

Screenshot 2017-05-10 20.38.20

Exposure of the contents to air forms a blackhead

Screenshot 2017-05-10 20.38.32

Bacteria (propionibacterium acnes) invade the hair follicle to feed on the excess oil

Screenshot 2017-05-10 20.40.00

Dead immune cells and bacteria result in pus production (pustule)

Other causes of acne


Oil based Cosmetics



    Taken internally

Greasy applications on the hair



The stages of Acne


  • Closed comedones (Whiteheads)

  • Open comedones (Blackheads)

  • Papules (Red bumps)

  • Pustules (Yellow pus filled bumps)

  • Nodules

  • Cysts

  • Scars



Can cosmetics be used in an acne sufferer?

Of course. Not only can they be used but their use is encouraged to cover up the marks left behind during the healing phase of acne, provided these cosmetics are not oil based. Furthermore, acne is not worsened by facials and deep cleansing of the skin.


What about basic skin care


The Vitasure range is the recommended skin care range in this practice.

A gentle cleanser such as Vitasure Gentle Cleanser is ideal for use twice a day.

Because of the dryness produced by many treatments, a moisturiser is useful for daily use. eg. Vitasure Day Cream.

Vitasure scrub is ideal for those who have many blackheads and whiteheads.

How is Acne treated?


Mild acne is treated with medicines which are applied on to the skin. The medicines available may be divided into several broad categories:


Salicylic acid preparations eg Aknicare

Benzoyl Peroxide eg. Benzac, Benoxyl

Antibiotics eg Ilotycin, Dalacin T

Retinoic Acid eg Retin A, Isotrex Gel

Naphthoic Acid eg Differin Gel/ Cream

Azaleic Acid eg Skinoren

Moderate to severe acne uses a combination of medicines taken internally with applied medicines.





What internal medicines are available?



        Tetracycline eg.

                   Lymecycline eg Tetralysal                  

                   Doxycycline eg Cyclidox, Doxycillin, Doryx, Dumoxin                  

                   Minomycin eg Minomycin, Minocin, Cyclimycin                  

                   Oxytetracycline, Roxy, O4cycline  (These must be taken 1/2 hour before meals and not with milk)

        Erythromycin eg Erymycin, Ilosone (Many patients are now resistant to this antibiotic)

        Cotrimoxazole eg Bacrtim, Purbac




Diane Generic equivalents:  Minerva (Schering), Ginette (Cipla Medpro)

Androcur Generic equivalent (Cipla ciproterone acetate - 50mg only)

Yasmin is a recently introduced oral contraceptive which has mild anti acne properties.  It can be used with androcur and makes a good substitute for Diane once the acne is clear.



Please click here for information on Roaccutane

Click here to see photos of patients treated with Roaccutane.



Physical treatments


Chemical peels


     Salicylic acid peels are particularly useful for comedonal acne (blackheads and whiteheads)

     Glycolic acid peels can be used for mild scarring

     Tricholacetic acid peels (TCA) is used for severe scarring.

Intralesional injections

Occasionally, large cysts (resembling boils) may develop on the skin.These may be treated with cortisone injections directly into the cyst. The injections may be repeated monthly if necessary. 

What's available for the scars?


Scar treatment is mainly surgical.  The following procedures are performed:

    punch excision

    punch elevation




    fractional laser treatment


Chemical Peels are used either at the onset of the treatment of acne or during the healed phase to assist with scarring


A silicone gel sheet called Scar Smooth can be applied on keloidal scars to flatten them.

Steroids injections can be given into keloids and cysts.




What can I use to speed up healing of a pimple?


MediPatch is a hydrocolloid dressing, available 36 to a box. Simply peel one off and stick it over a pimple to speed up its healing. It also prevents squeezing. Available from the practice or a pharmacist near you.


Does an antibiotic get rid of acne permanently?


Antibiotics are able to control but not cure acne. It is possible for the antibiotic to work to such an extent that no acne is visible whilst taking the antibiotic. However, when the antibiotic is stopped, the acne may return after a variable period of time - usually several months.


The same antibiotic may be taken again if it worked the first time. If the antibiotic looses its effect on the acne, it may be changed to a different one.

The only medication that is associated with a cure is Isotretinoin (Roaccutane/ Oratane / Acnetret / Acnetane). As much as 70% of patients who take Roaccutane never see the acne again. Bear in mind that acne can recur in 30% of patients who have taken isotretinoin. 

I am pregnant. What can I use for my acne?


The following medications may be applied topically during pregnancy

Glycolic acid (over the counter)​

The following topical medications are classified as Pregnancy Category B



Azelaic Acid


Oral medication are not the first line treatment for acne in pregnant women.

However, if required, the following may be used:




The above oral medications are also classified as pregnancy category B

Since clinical studies are not performed in pregnant women, such information is not available in humans. Medicaions tested in pregnant women and found to be safe would have carried a Pregnancy Category A classification.

Pregnancy Category B refers to medicaitons that were tested in pregnant animals and showed no risk to the foetus and therefore are presumed to be safe in pregnant women.

For more information, please see

I am not keen on using any oral medicaton. What alternatives are there?

Photodynamic therapy using blue light alternating with red light for 4 weeks (2 treatments per week - 1 red, 1 blue) for 4 weeks. The light destroys Propionibacterium acnes - the bacterium which causes acne.

Chemical peels and microdermabrasion are other possibilities.


Useful links:

American Academy of Dermatology Acnenet.

New Zealand Dermnet - Acne

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Example of patient treated with Tetralysal antibiotic taking 3 months to achieve complete control. Pics Dr N Raboobee

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