Vomiting from allergies?

My mothers boyfriend is an "ex" cocaine addict and ex alcoholic. My mother barley knows this guy and now he is living with her. My question is that he claims he is allergic to dogs. ( which we have and he uses as an excuse to never come over to our house)  We have never seen him, sneeze, blow his nose, get watery eyes, itch. My mother says that he vomits every single morning, and that is due to allergies. He is often drinking when we see him and when he comes home from work he often smells like alcohol. Before I cry B.S to this guy I want to make sure that I am not accusing him of something that might be possible. I have two 2 month old twin girls so if this guy is not legitimate I need to know. I just think it is strange that vomiting is his ONLY symptom. I have been around people with allergies and this is not what I see from them. If it is a real problem what kind of treatment would help with that vomiting from allergies?

[Dr Rajput]

Hi, it is difficult to relate the vomiting with exposure to dog but it can be possible and rare. Basically he may be allergic to the dog and few individuals who develop allergy they can manifest as vomiting without any skin rash or swelling. Sometimes this condition is known as cyclic vomiting syndrome where allergen is one factor which is implicated in it.
The treatment can involve treatment with anti emetics when he is exposed to the dog. Secondly, a course of anti histaminics is worth trying and it is known to desensitize the vestibular system which is known to trigger the vomiting through vomiting centre.
Thirdly, he can be desensitized by exposing the dog stepwise manner under medical supervision until he is tolerant to further exposure. But the effectiveness of such procedure is questionable.
I suggest him to consult immunologist for further evaluation. Take care and regards.

[Dr Rajput]

Hi, it is difficult to relate the vomiting with exposure to dog but it can be possible and rare. Basically he may be allergic to the dog and few individuals who develop allergy they can manifest as vomiting without any skin rash or swelling. Sometimes this condition is known as cyclic vomiting syndrome where allergen is one factor which is implicated in it.
The treatment can involve treatment with anti emetics when he is exposed to the dog. Secondly, a course of anti histaminics is worth trying and it is known to desensitize the vestibular system which is known to trigger the vomiting through vomiting centre.
Thirdly, he can be desensitized by exposing the dog stepwise manner under medical supervision until he is tolerant to further exposure. But the effectiveness of such procedure is questionable.
I suggest him to consult immunologist for further evaluation. Take care and regards.