What to do if i have severe asthma and dog allergies can i get a dog?

Avoidance is the: Safest option. You could see an allergist for desensitization as another option.

No: If you have severe allergy to dogs you should probably not get a dog

Why ?: If you know it will hurt if you jump off a building wouldn't you avoid it. There is no magic treatment that would allow you to have a dog if you have severe symptoms from exposure.