There are lots of things in world that are beneficial for the human kind. At the same time there are also things that harms us. We know many things that are poisonous and if we consume them, it may lead even to our death. Like wise, there are things that can could cause allergies to humans.
But here we’re talking about weird allergies that people are allergic to various day-to-day life things. For example, some people are allergic to powders, no matter how good the powder is, still they might get suffocated even if they get to smell its small fragrance. Similarly here are some things that we use daily, which are allergic to different people due to their specific diseases.