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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

Salicylic acid

Salicylic acid belongs to a group of medicines known as keratolytics. It is used in the treatment of scaly skin diseases where the skin has become thickened, scaly and flaky. Topical preparations of salicylic acid, either alone or in combination with other medicines, can be used to treat the following common scaly skin conditions:

How does salicylic acid work?

Salicylic acid works by softening keratin, a protein that forms part of the skin structure. This helps to loosen dry scaly skin making it easier to remove. When salicylic acid is used in combination with other medicines it takes off the upper layer of skin allowing the additional medicines to penetrate more effectively.

In acne, topical salicylic acid helps slow down shedding of the cells inside the follicles, preventing clogging. Salicylic acid also helps break down blackheads and whiteheads.

Salicylic acid preparations

Salicylic acid preparations come in many forms and strengths. Available dosage forms include cream, gel, lotion, ointment, pads, plaster, shampoo, cleanser and topical solution. Strengths of salicylic acid preparations range from 0.5% up to 30%. The form and strength chosen depends on the condition that is being treated.

Listed below are a few of the many salicylic acid preparations available in New Zealand.

Preparation Topical form Indications
Salicylic acid 2-3%, Betamethasone 0.05% (Diprosalic®) Lotion
Hyperkeratotic eczema
Salicylic acid 15-27% (Duofilm®) Paint
Viral warts
Salicylic acid 2%, Coal tar solution 12%, Sulphur 4% (Coco-Scalp®) Ointment Seborrhoeic dermatitis
Scalp psoriasis
Salicylic acid 0.5% oil-free acne wash (Neutrogena®) Cleanser Acne

Whilst many salicylic acid preparations are available from a pharmacy, some preparations are only available on a doctor's prescription. These include preparations containing a combination of salicylic acid and topical corticosteroid, e.g. Diprosalic®.

How to use salicylic acid preparations

Side effects of topical salicylic acid preparations

Salicylic acid preparations are usually well tolerated. Mild stinging may occur especially on broken skin and when higher concentrations are used. Salicylic acid can irritate or burn healthy skin so it is important to keep the medicine confined to the affected area(s). Check with your doctor if you:

True allergy to topical salicylic acid is rare, however serious reactions including anaphylaxis have been reported.

Salicylic acid poisoning (overdose) with topical preparations is rare. Symptoms of poisoning include confusion, diarrhoea, nausea, vomiting, dizziness, headache, rapid breathing, continuing ringing or buzzing in ears, severe drowsiness.

Precautions when using topical salicylic acid preparations

When using salicylic acid preparations do not use any of the following preparations on the affected area, unless directed to do so by your doctor.

Inform your doctor if you are pregnant or breast-feeding. Salicylic acid can be absorbed through the mother's skin. The risks and benefits will need to be discussed with your doctor before using any preparations containing salicylic acid.

Salicylic acid preparations should not normally be used in children younger than 2 years. Use in young children should be monitored carefully as children are more likely to get skin irritation and the absorption through skin is greater.

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Author: Vanessa Ngan, staff writer

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