Brief Answer:
consider using an antihistamine to reduce the reaction

Detailed Answer:

Hi,

If it happened after the use of your blood thinner, it may mean that you are allergic to that particular medications.
Allergic reactions can occur even after medications or foods or drinks etc have been used for a long period of time. The body builds up a reaction to it. If you do not think that it was the blood thinner then you may want to consider allergy testing.

Allergy testing can be done for some meds, foods, drinks or environmental allergens (dust, pollen, animal dander, mold etc)

You can use an anti histamine to help treat the reactions. Antihistamines such as benadryl can be used, it does not react with the commonly used anti coagulant meds such as pradaxa, xarelto, eliquis

You may also need to tell your doctor about the reaction.

I hope this helps, feel free to ask any other questions

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