Sunburn susceptibility can have various causes, ranging in severity from 'very minor' to 'needs attention'. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose sunburn susceptibility, we could:
Compared to other people with similar skin color, how quickly do you sunburn?
Possible responses:→ I sunburn very quickly, much faster than most
→ I am sometimes more easily sunburned than others
→ About average / don't know
→ I don't easily get sunburned compared to others
→ I burn much slower than most people my skin color