Hi, Thanks for writing in. The long term outlook of the problem that your son is excellent. Please do not worry. As far as the causes of this are concerned, it seems to be allergic in his case as the lesions appear with change in season. Other causes include Other cases of erythema annulare centrifugum have been found in association with an underlying systemic or infectious disease (eg, liver disease, Sjögren syndrome, systemic lupus erythematosus, Graves disease,hypereosinophilic syndrome, appendicitis), herpes zoster, chronic lymphocytic leukemia, and HIV. Drugs reported to cause EAC include finasteride, piroxicam, hydroxychloroquine, amitriptyline, and spironolactone. In some people, it runs in families. I am sure his doctors ruled out all these conditions and you dont need to worry. Children can outgrow their allergies and you son will be fine very soon Regards