Liminality in medicine is the idea that you can be between illness and wellness.

Paul Turner et al give the example of having a food allergy: people with allergies do not consider themselves fully ‘ill’ or entirely ‘well’, but something in between. They are typically “well” so long as they apply food safety skills to avoid their trigger food(s) – but a slip or mistake can lead to a reaction and potentially death from anaphylaxis.

With liminality, a young person feels set apart, or a family feels their child is different from others – this can impact on self image, social interaction, which in turn can lead to denial or other unhealthy coping strategies and adverse health outcomes.