Firstly, illness and fasting have rulings:
1- Either the illness is chronic, and the person is unable to fast with no hope of recovery, such as with most types of diabetes, high blood pressure, kidney or liver failure, and others. If the doctor advises that fasting is harmful, the patient should refrain from fasting, as preserving one’s health takes precedence over other religious obligations in such cases. This patient is required to make up for each missed day of fasting through expiation, which is two meals according to the Hanafi school of law, and one meal according to the majority of scholars for each missed day. However, if the patient is poor like the one who is asking this question, the expiation is waived, as Allah says in the Quran, “Allah does not charge a soul except [with that within] its capacity” (Al‑Baqarah, 2:286), and “Allah does not charge a soul except [with that within] its capacity” (Aṭ-talāq, 65:7). The Prophet (peace be upon him) also said, “Whatever I command you to do, do it to the best of your ability.”
The fundamental principle in Islamic law is to remove hardship from people, and one is not demanded of what is impossible or what is in its ruling.
2- The illness is not chronic, but it worsens with fasting or it is suspected that recovery will be delayed. In this case, the person is exempted from fasting, but they are required to make up for the missed days of fasting when they recover. If the illness becomes chronic before recovery, then the person must provide fidyah, and the ruling on this will be the same as the previous case.
3- The illness is a mild one that can be tolerated with fasting, even if it causes some discomfort such as headaches or localized pain in the body, and does not require urgent or permanent treatment. . In this case, the person is not allowed to break their fast because there is no extreme hardship involved, and the basic principle is that fasting involves some degree of hardship. If the person breaks their fast in this case, they will be considered as deliberately breaking their fast and will be subject to the same ruling as someone who breaks their fast intentionally.
Therefore, in summary, for the asthmatic patient who has been advised by a doctor to break their fast, there is no thing upon her due to her state of need and necessity.
And Allah knows best.
Fatwa by Dr. Khālid Naṣr