DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Imiquimod is a an immune response modifier. It is manufactured as a 5% cream called Aldara™. A 3.75% cream called Zyclara™ has also been approved by the FDA in the USA, but is not yet available in New Zealand (June 2013). Imiquimod is mainly used to treat genital warts, actinic keratoses and basal cell skin cancers.

Imiquimod works by stimulating the immune system to release a number of chemicals called cytokines, which are important in fighting viruses and destroying cancer cells.

When used to treat skin cancers and pre-cancerous lesions it results in inflammation, which destroys the lesion. The degree of inflammation is quite variable from person to person, in part due to the type of skin lesion and in part due to genetic factors. The imiquimod is taken up by the so-called ‘toll-like receptor 7’ on certain immune cells that are found in the outside part of the skin (the epidermis); these receptors are expressed more in some individuals and in some skin lesions than in others.

Imiquimod is particularly useful on areas where surgery or other treatments may be difficult, complicated or otherwise undesirable, especially the face and lower legs.

A course of treatment ranges from 4 to 16 weeks. Before starting, a biopsy may be performed to confirm the diagnosis. Treatment should be carefully monitored, because the cream may need to be applied more or less frequently than originally planned or for a shorter or longer course, depending on response. Once the inflammation has settled there is generally a good or excellent cosmetic result with little scarring.

Imiquimod is particularly useful for:

It is also used to treat viral infections, especially genital warts. It may also be helpful in the treatment of common warts (once they have been thinned down by other means), plane warts, and herpes simplex. Experimentally it has been successful in reducing some keloid scars, granuloma annulare, vitiligo, melanoma in situ and, in combination with diphencyprone, metastatic melanoma (see topical and intralesional immunotherapy for melanoma.

Although sometimes prescribed for molluscum contagiosum, clinical trials have not shown imiquimod to be of benefit.

Treatment regimes for imiquimod

Various imiquimod treatment regimes are used. For example:

Apply the imiquimod less often if the reaction is excessive, and more often if no reaction occurs. Check with your doctor; he or she may recommend a different regime in your case. Treatment is sometimes continued for up to 16 weeks.

How to use imiquimod cream

Wash your hands before and after applying imiquimod cream.

Cut the top off the sachet or pierce the sachet with a needle and squeeze out a tiny amount of cream onto your fingertip. Apply this to the affected areas.

Although the information on the packet states that the sachet is for single use, you could seal it using a paper clip or tape and store in a closed container to prevent the cream drying out.

Imiquimod may be used at any time of year, as it is not photosensitising. However, when outdoors, you should protect yourself from the sun with clothing and sunscreen as usual.

What to expect from imiquimod cream

Areas treated with imiquimod will be come inflamed. The effects include itching, burning, redness, ulceration (sores), scabbing, flaking and pain. These reactions indicate that the cream is likely to be effective - if there is no inflammation, imiquimod is unlikely to clear the lesions. An exaggerated response may clear the skin lesion sooner than expected - sometimes after as few as three or four applications. In some patients, surrounding untreated areas also become inflamed but this will settle when treatment is discontinued.

If you develop a severe reaction with black scabs and ulceration, stop applying the cream and arrange to see your doctor as soon as possible.

BCC prior to treatment
Imiquimod to BCC
BCC: During treatment
Imiquimod to BCC
BCC: After treatment
Imiquimod to actinic keratosis
SKs: Mild reaction
Imiquimod to actinic keratosis
SKs: Moderate reaction
Imiquimod to actinic keratosis
BCC: Severe reaction
Effect of imiquimod

More images of the effect of imiquimod ...

Systemic side effects from imiquimod cream

When using imiquimod cream, 'flu-like symptoms may develop, such as fever, fatigue, headache, nausea, diarrhoea and muscle pain. These are generally mild and may be treated with paracetamol. However, if they are troublesome, stop applying imiquimod cream and contact your doctor. Side effects should resolve within a few days of stopping treatment. They may also resolve with continuing treatment.

Make sure you have made an appointment for follow-up with your doctor.

Related information


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Author 2000: Steven Lamb MBChB
Update 2003, 2004 by Darion Rowan FACD and Amanda Oakley FRACP.


The New Zealand approved datasheet is the official source of information for this prescription medicine, including approved uses and risk information. Check the New Zealand datasheet on the Medsafe website.

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.