Thank you for your query on Healthcare Magic,
Repeated cold is due to frequent exposure to viruses causing rhinitis
or due to some allergy
Primary complex doesn't present with repeated cold.
Don't give antibiotics without prescription and sipmle cold doesn't require any antibiotic as it is usually caused by a virus or due to allergy.
Just symptomatic treatment is required with oral antihistamines like cetirizine
If you want to rule out Primary complex, you can go for CBP, ESR, Mantoux testing, and chest x ray after consulting your Pediatrician
Primary complex of your childhood doesn't lead to primary complex in the child if you are treated promptly and if you don't have tuberculous problem (especially lung involvement) since her birth.
For weight gain give balanced and nutritious diet daily.
Hope I have answered your query, if you have any querie you can consult me in future on Healthcare Magic.