For those triggers that cannot be avoided, you can try to compensate with extra care in other ways. For example, when your child has a cold, you can try to ensure he gets lots of sleep and nutritious foods. Some triggers may become more of an issue as your child gets older.
barnacle. n. 1. (Animals) any of various marine crustaceans of the subclass Cirripedia that, as adults, live attached to rocks, ship bottoms, etc. They have feathery food-catching cirri protruding from a hard shell. See acorn barnacle, goose barnacle.
Barnacles are a very variable species, but the parasitic variety usually infest sharks, sea turtles, and baleen whales. Faster moving whales are usually immune from barnacle infestation because the barnacle feeds better in slower moving water and can stayed attached to their host more easily.