The service industry is fraught with illness and the risk of infection. As per any food service job, its pretty frowned upon for your health or beauty practitioner to be sick while trying to help you.
Allergies are not something that one can help, but major sickness is something else. Head colds, fever, flu or food poisoning, for example, are not something that should be allowed to be worked through in a service industry job.
It is, however, common courtesy to inform your clients of these health impediments before their scheduled appointments. When working in a walk-in environment, it is customary to get your shift covered. For this, I apologize profusely for my absence on Tuesday. It was not acceptable behavior, and for as much as I proselytize about professional behavior, I fell short of the mark to which I hold others. I am so sorry that I missed work on Tuesday. Food poisoning is not something that I wish upon anyone. Had I been able to get out of bed, I would have. But unfortunately, I was unable to function in any useful manner until around 11am today.
I am so sorry.