Thimerosal (Merthiolate)

This patient information on Thimerosal is provided by John L. Meisenheimer, M.D. a board certified Dermatologist and skin care specialist based in Orlando, Florida. This information is not intended as a substitute for the medical advice or treatment of a dermatologist or other physician.


The results from your patch testing showed a positive reaction (contact allergy) to Thimerosal. Your immune system reacts with its defense mechanisms with each exposure of Thimerosal to your skin. It is unknown why certain individuals develop allergic sensitivities. In some it may take repeat exposures over long periods of time before an allergy develops. Once you have become sensitized (allergic) your immune system always “remembers” and you will be Thimerosal sensitive. If you currently have eczema this chemical may be the cause but other factors may play a role as well. The information below will help you avoid this allergen.

Used widely as an antiseptics and preservative in topical medications cosmetics, and vaccines.

Individuals’ that show a positive reaction to Thimerosal may be more of a risk to develop a photosensitivity to Felene (Piroxicam) an oral anti-inflammatory.

Where is chemical found?

Antitoxins
Antiseptics
Cosmetics
Contact lens solution
Desensitization injections (allergy shots)
Ear drops
Germicides
Immunogloblin preparations
Allergy skin testing solutions
Liquid soap
Mascara
Nose drops
Oral hygiene products
Pesticides
Soap-free cleanser
Topical medicines
Tuberculin tests
Vaccines

Hints on avoiding chemical:

Choose products listed only on your personalized Contact Allergen Database, which has been provided to you. Products listed on your Contact Allergen Resource Database will be free of Thimerosal and safe to use.
Please be aware that if your spouse or significant other uses topical skin care products that contain this chemical skin-to-skin transfer may occur to you.
It may take 2 to 3 weeks of avoiding exposure before improvement of your eruption begins.
Inform your primary car physician about your allergy and ask for preparations that do not contain thimerosal.

Other names you may see this chemical listed as:

Ethylmercurithiosalicylate
Mercurochrome
Mercurothiolate
Merfamin
Mertorgan
Merthiolate
Merzonin
Sodiumethylmercurithiosalicylate
Thiomersalan
Thiomersalate

Potential Occupational Exposures:

Nurses
Laboratory Technologists

© John “Lucky” Meisenheimer, M.D.  2019                                   WWW.OrlandoSkinDoc.com