There are a lot of small bumps on the arm, a little itchy

There are a lot of small lumps on the arm a little itchy mostly caused by urticaria, you can use loratadine, cetirizine and other drugs for treatment, if necessary, you can add glucocorticoids. Pay attention to stay away from allergens, drink plenty of water, promote allergic substances discharged. Diet should be light, it is best not to eat seafood.