After receiving influenza vaccine, infant cried Was going to checkout, cried more and then was choking. Colored witnessed to turn red and medical staff was alerted. Pulse ox 98%, HR 137, Resp 24. Infant noted to be flushed all over body and even some acrocyanosis of feet but cap refill < 2 secs Heart RRR no murmur and lungs clear. Given Benadryl 5ml orally. Color was spontaneously gradually turning to normal. Recheck prior to dc 10 minutes later Happy, normal color RRR , lungs clear, pulse 130, pulse ox 97%