What you should know about Thimerosal allergy

Updated: Aug 23, 2020

Thimerosal is a chemical preservative that contains ethylmercury and thiosalicylate. It is a light colored crystalline powder that is found in personal care products, makeup and childhood vaccines. It is also found in ophthalmic (eye) and otolaryngology (ear) medications, antitoxins, topical and intramuscular steroid preparations as well as intradermal tests.

The use of thimerosal in children and adults with autism can produce unwanted side effects and patients and their families should communicate their desire for alternative means of immunization. Physicians also usually recommend that siblings of those with autism take the same precautions. People who suffer from autism should also keep thimerosal out of their personal care products, makeup and any other medications such as eye drops or throat sprays.

Common places this preservative is found include but is not limited to:

  • Eye ointments

  • Contact lens solutions

  • Eye drops

  • Antibiotic ointments

  • Antitoxins

  • Cosmetics

  • Makeup removers

  • Eye moisturizers

  • Soap free cleansers

  • Nose drops

  • Tuberculin testing

  • Desensitization solutions

According to the North American Contact Dermatitis Group a Thimerosal Allergy is the fifth most common allergen that affects people in the United States. (1)

While completely removing thimerosal from the individual environment may be almost impossible it is possible to reduce the daily exposure by using makeup, cosmetics, make up removers and contact lens solutions without the chemical.

A thimerosal allergy is often found only on the skin. Patients who have allergic reactions to the chemical may find that they develop a rash around an injection site or have a severe conjunctivitis from the preservative found in their contact lens solution.

There are groups of people who appear to be more at risk to a thimerosal allergy. These include women, cooks, and healthcare workers. The increased thimerosal allergy reactions in these groups maybe because of the increased exposure. Women often use makeup and contact lens solutions with the preservative and cooks and healthcare workers are often exposed through the immunizations they are required to receive for their work.

Thimerosal is also known as Mercurochrome, Merzonin, Merthiolate, Mertorgan, Sodium ethyl mercuri thiosalicylate, Merfamin, Thiomersal, Thimerosal, and Thiomersalate. This isn't a comprehensive list of the various chemical names used for this preservative.

Although there may not be obvious allergic reactions, or side effects, of the use of this preservative in people who arenít allergic the question remains ñ what reactions are being initiated in the bodies of adults and children who are exposed to this preservative in their antibiotics, immunizations and personal care products?


Journal of the Medical Association of Thailand: Thimerosal Allergy and Clinical Relevance in Thailand

Journal of American Academy of Dermatology: Thimerosal in the Detection of Clinically Relevant Allergic Contact Reactions

Centers for Disease Control and Prevention: Frequently Asked Questions about Thimerosal

Medscape Today: Hypersensitivity Reactions to Vaccine Components

Contact Dermatitis: Hypersensitivity to Thimerosal: The Sensitizing Moiety

US Food and Drug Administration: Thimerosal in Vaccines

Journal of the American Academy of Dermatology: Thimerosal in the Detection of Clinically Relevant Allergic Contact Reactions

American Academy of Allergy Asthma and Immunology: Allergy to Thimerosal;-any-cross-reactivity-with-m.aspx

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