Mothers have been reporting that they have been advised to interrupt breastfeeding or even stop altogether in order to have skin and patch allergy testing. This doesn’t seem based on evidence but possibly without national guidelines.
The allergens do not pass into the blood stream let alone breastmilk so there is no reason to interrupt breastfeeding.
Should you react severely to an allergen test and require administration of an antihistamine, an adrenaline injection (e.g. EpiPen) or a steroid that does not stop you breastfeeding as normal
Adrenaline/epinephrine injection e/g/ EpiPen ™. Ingredient present in milk but unlikely to be harmful as poor oral bioavailability . Half life 2 minutes so all gone from the body in 10 minutes.
Antihistamine – https://www.breastfeedingnetwork.org.uk/antihistamines/
Prednisolone – https://www.breastfeedingnetwork.org.uk/prednisolone/