If there is recurrent enlargement of lymph nodes, you could check to see if any of the draining areas have any evidence of infection
, like tonsils, the skin, tooth
abscess or an ear infection
. Infections like tuberculosis can cause lymph adenopathy. It amy not be realted to the rash. It would be worthwhile to see if other lymph groups are enlarged namely, axilla and groin, these can be palpated, the others like those in the chest or abdomen may need a CT to detect their enlargement.