The wide use of topical antibiotics in the past
has lately resulted in a big increase in bacterial resistance
against these drugs.
Reducing bacterial resistance to topical antibiotics is now one
of the main aims with acne therapy. With this end in view, antibiotics
are now being used for only short periods in combination with
retinoids and antimicrobials such as benzoyl peroxide and azelaic
Azelaic acid is a naturally occurring saturated decarboxylic
acid that was first tried out in the 1970s in Europe as a treatment
for hyperpigmentation of the skin. By chance it was also found
to be an effective medication for acne. Various studies have confirmed
this finding. These studies have also established that its efficacy
in treating a number of skin problems including, comedonal, as
well as, inflammatory acne lesions, is equal to other topical
medications. Limited studies show that it works as well as oral
tetracycline without any of its side effects. It is now considered
an antimicrobial and it is recommended for treating mild to moderate
acne, that is, both comedonal and inflammatory acne. However,
it is mostly recommended as a second line of treatment.
The mechanism by which it acts is not known as yet, but it has
been shown to exhibit antibacterial and anti-keratinizing properties.
Its antibacterial properties reduce bacteria in the follicle.
It works, it seems, partly by reducing the production of bacteria
on the skin, keeping the skin pores clear and by reducing the
production of keratin which is a natural substance that may lead
to development of acne. It returns to normal the disordered growth
of skin cells lining the follicle. Azelaic acid works well on
acne caused by bacteria but has no effect on acne that is not
infected by bacteria.
Azelaic acid does not cause bacterial resistance. Also, unlike
benzoyl peroxide, azelaic acid does not bleach or stain normal
skin or clothing. It is not photosensitive, for which reason it
is particularly useful in summer time. It is also useful in patients
who cannot tolerate topical retinoids. Azelaic acid helps reduce
pigmentation, so it is particularly useful for dark skinned patients
whose acne leaves persistent brown marks or who have cancerous
melasma. However, patients with dark skin should be monitored
for hypopigmentation (too little skin color). It should be used
with caution in lactating or pregnant women.
Azelaic acid is applied topically and is well absorbed. It is
available as a 20% cream and as a gel preparation that has been
recently introduced. The normal procedure is to apply azelaic
acid to the area affected by acne after thoroughly cleansing the
skin. The cream is initially applied once daily and if well tolerated
the application is increased to twice daily. In case of patients
with sensitive skin, to begin with, azelaic acid may be applied
once in two days and then the frequency gradually increased to
give time to the skin to adjust. Contact with eyes should be avoided.
The response of acne to azelaic acid treatment is slow. Normally
improvement is seen after one month of treatment. Continuing application
of the cream shows further improvement with maximum results usually
obtained after six months of continuous treatment. Treatment can
be continued safely for months or years if the acne remains active.
To date there have been no reports of serious side effects of
the drug. Azelaic acid is non-toxic and fairly well tolerated
with only 5% of patients having any complaints about side effects.
When side effects do occur they are typically one or more of skin
irritation, burning, stinging and erythema. Benzoyl peroxide and
tretinoin have a higher complaint rate. Those with sensitive skin
or who suffer from eczema may especially find azelaic acid irritating
to apply since a mild irritant dermatitis may result.