Can partialy treated ear infec cause strep throat in 6yr old he took amxicil for 6.5 days & cefdnir a month later for 10 days fr strep. Complications?

Yes & no. Group a strep can cause an ear infections but it accounts for a small minority.Partial treatment can prevent primary cure, but some ears can reinfect when the fluid behind the drum remains.( often up to 6 wks)to me strep complications include kidney disease, rheumatic fever or neurologic disorders related to strep a. Persistence after inadequate treatment is expected, not a complication.