Final answer:
Significant observations during hygiene assistance, including potential health issues, should be reported immediately for proper care.
Step-by-step explanation:
Observations made while assisting with hygiene that should be reported at once include any unusual or concerning findings that could indicate a health issue or require immediate attention. This generally does not include all observations, but rather those that are significant and have implications for the individual's health or safety, such as signs of infection, sudden changes in skin condition, unexplained bruises, or allergic reactions. Prompt reporting allows for timely interventions and care adjustments as necessary.