When someone says they have an itchy
nose, it could be from allergies.
BUT if you mentioned a certain topic or person and they suddenly have an itchy nose, they only scratched it so their
hand would cover their facial expression.
For example, if somebody blushes and they
don’t want you to know, will they cover their face (which is clearly a way of saying “I
don’t want you to see me), or will they suddenly have an “itchy nose” and be “forced” to cover their face? Think about it.