My advice would be to always check with your training manual, college notes and confirm suitability with your insurance provider if you really aren't sure.
Generally speaking we would turn away someone with an illness, fever or headache on the day of their treatment. It would be best postponed until they feel better.
However ongoing cancer treatment, un medicated high blood pressure, or other illness whereby the client is under the care of their GP or hospital would be a no to treatment, until they are on a suitable treatment plan. Diabetics (type 1) I would not treat.
Clinicians can often give permission as was the case of one of my clients that had a stroke. Once treatment is sorted she is now fit to carry on with life and that means can have massage/ facials/ waxing with no problems. Obviously in the case of blood thinners , I am wary of doing anything that would be too firm pressure- wise to cause bruising. So use your common sense around adaptation. Lighter effleurage mainly would be one such adaptation. If you struggle making a judgement you should say no.
Hot towels and back scrub type treatments are quite a nice alternative to full body massage. Foot and leg, hand and arm scrub and dermal wraps can be useful if full body massage is out of the question. Hope that helps.
