“There is no evidence that tobacco smoke causes allergic reactions.” It is likely that the smoke causes a reflex response in the nose causing increased nasal congestion etc. Avoidance is advised although it is possible that oral decongestants, intra-nasal antihistamines or intranasal steroids can be helpful in relieving some of these symptoms.
Wouldn’t a person have to be actually smoking to cause this ‘irritation’? I don’t think you can have an allergy to a smell.
The woman probably just wasn’t clean and she stank. I can't imagine that 8 cigarettes a day would be enough to get her fired because of the smell.