What is clioquinol and where is it found?

Clioquinol is a quinoline compound that has antibacterial and antifungal properties. It is found in topical preparations to treat skin infections such as infected eczema, athlete's foot and other fungal infections. It is also found in combination preparations with hydrocortisone. It can be found in eye and ear preparations.

Other quinoline compounds available include diiodohydroxyquinoline, chlorquinaldol and chlorhydroxyquinoline.

What are the reactions to clioquinol allergy?

Clioquinol sensitivity produces classic allergic contact dermatitis reactions. Sometimes the condition the topical medication has been used to treat for worsens or there are no signs of improvement with use. There may be increased irritation, redness, itching or burning around the infected area.

Am I allergic to clioquinol?

Allergic sensitivity to clioquinol is usually only picked up when a skin infection being treated with clioquinol fails to respond to treatment or worsens. Clioquinol allergy is diagnosed by performing special allergy tests, i.e. patch tests with clioquinol 5% in petrolatum.

Allergy to clioquinol may also mean you are sensitive to other quinoline compounds.

Treatment of clioquinol allergy

Confirmation of clioquinol allergy requires the prompt removal of the causative agent and then management as for any acute dermatitis/eczema; this may include treatment with topical corticosteroids, emollients and treatment of any secondary bacterial infection (Staphylococcus aureus), etc.

What should I do to avoid clioquinol allergy?

You must avoid using any preparations that contain clioquinol or any of its alternative names. You should also avoid preparations containing any other quinoline compounds. Always alert your doctor to the fact that you have a contact allergy to clioquinol so that they can prescribe you suitable alternatives if necessary.

If purchasing over-the-counter products alert your pharmacist to the fact that you have a contact allergy to clioquinol. They should be able to provide you with a suitable alternative.

Your dermatologist may have further specific advice, particularly if you are highly sensitive to clioquinol.

Alternative names for clioquinol

Clioquinol is also known by several other names. These include:

• Iodochlorhydroxyquin
• Iodochloroxyquinoline
• Iodochlorohydroxyquinoline
• Chloroiodoquine
• Vioform

Further information

Formula:C₉H₅Cl₅NO

CAS number: 130-26-7

Cross reactions: diiodohydroxyquinoline, chlorquinaldol and chlorhydroxyquinoline.

Sensitiser: clioquinol

Patch Test: 5% clioquinol in petrolatum

Reference

Book: Fisher's Contact Dermatitis. Ed Rietschel RL, Fowler JF. Lippincott Williams & Wilkins 2001