Sick again!

Every 3 to 4 weeks my son has been getting sick for the last three months. The first two times he had the same symptoms: Sneezing, runny nose and congestion, watery eyes, and a temp that would linger for several days. This time it started off the same but with no temp. He’s on day six of just straight congestion. He doesn’t go to daycare so I thought maybe it was allergies. He’s been getting Claritin the last three days and really no improvement. Anyone have something similar or any suggestions?