How to prepare the solution?Thyroxin solution for skin testing can be prepared by crushing a tablet (50 mcg) and mixing with 1 mL of 0.9% phosphate-buffered saline for 2 hours.
The solution can be passed through a 0.2-micrometer-pore filter if future IV administration is indicated. This should be done by a pharmacist.
How to do the skin test?
Prick test with levothyroxine solutiion, 50 mcg/mL. If negative, do intradermal testing with 0.02 mL of the solution in concentrations of 1:100,000, 1:10,000, 1:1,000, 1:100, and 1:10.
If the tests are negative, a challenge with levothyroxine should be performed if indicated.
Drug allergy management in 5 steps (click to enlarge the image).
References:
IMMEDIATE-TYPE HYPERSENSITIVITY REACTION TO LEVOTHYROXINE AND DESENSITIZATION - Annals of Allergy, Asthma & Immunology http://buff.ly/1BHCa1C
Levothyroxine anaphylaxis? Vocal cord dysfunction mimicking an anaphylactic drug reaction - Annals of Allergy, Asthma & Immunology http://buff.ly/1FF8r6F
https://www.annallergy.org/article/S1081-1206(10)61679-1/pdf
Successful oral desensitization to levothyroxine. Demirel Fevzi et al. Annals, 2013.
https://www.annallergy.org/article/S1081-1206(13)00395-5/fulltext
https://www.annallergy.org/article/S1081-1206(13)00395-5/pdf
Ask the Expert, AAAA.
https://www.aaaai.org/ask-the-expert/desensitization-levothyroxine
Image source: Wikipedia, public domain.
