What is the standard for determining if an illness permits breaking the fast?
General Chapter
Al-Mughni
Book of Fasting
Primary text
The ruling on breaking the fast is established by the fear of harm, which is the underlying wisdom behind the concession for the sick. The criteria for an illness permitting the breaking of the fast is one that is feared to increase due to fasting or prolong recovery. This fear of potential harm justifies the concession, unlike in travel where the allowance is based on the mere designation of long travel (the presumptive standard, *mizannah*), because illness varies greatly, and some ailments like a toothache, minor finger wound, simple ulcer, or scabies do not warrant breaking the fast if the harm can be assessed directly.
Supporting text
A healthy person who fears contracting an illness from fasting is treated analogously to a sick person who fears the exacerbation of their existing condition, as the fear of a newly induced ailment is equivalent in meaning to the fear of an existing one worsening.