If you talk about a rash of events or things, you mean a large number of unpleasant events or undesirable things, which have happened or appeared within a short period of time.
双语例句
例: one of the few major airlines left untouched by the industry's rash of takeovers.
在这一连串的行业兼并中少数几个未被波及的大航空公司之一。