There are a number of causes for allergic reactions to eyelash extensions. An allergic response to the adhesive used to affix the extensions to the natural lashes is one frequent cause. The adhesive contains substances including formaldehyde, cyanoacrylate, and latex that, in some people, might irritate their skin and trigger allergic responses.

An allergy to the components of the eyelash extensions themselves is another potential factor in allergic reactions to eyelash extensions. For instance, some eyelash extensions are made of animal fur, which can make those with animal sensitivities react negatively.

Additionally, some people may be sensitive to the fumes that are produced during the application of eyelash extensions. The fumes can cause irritation to the eyes and respiratory system, leading to symptoms such as coughing, sneezing, and watery eyes.

In rare cases, an allergic reaction to eyelash extensions can cause more severe symptoms such as difficulty breathing or a swollen throat, which can be life-threatening.

Overall, there are several potential reasons why someone may be allergic to eyelash extensions, including an allergy to the adhesive, materials used, or fumes produced during application. If you suspect that you are allergic to eyelash extensions, it's important to seek medical attention and discontinue use of the extensions.