Welcome to Healthcaremagic forum,
The red bumps seems to be some kind of allergic reaction
known as papular urticaria
To begin with you can try taking some anti histaminics like cetrizine
tablet (10mg) daily for few days and see the response. Since other members of the family are not affected I would rule out scabies or bed bugs.A detail history and a picture of the lesion would help me further to guide you better.
Hope this answers your query,
wish you good health,