This may have actually masked the symptoms of his real illness, though they asserted themselves soon enough.

Ministers are right, however, to resist calls for widespread vaccination of flocks, which could simply mask the symptoms and spread the problem.

It's the first product on the market that fights colds at the early signs rather than masking the symptoms.

In your case living with someone who was presumably following a gluten-free diet may have masked your symptoms if you were keeping them company and doing the same.