How can one differentiate between afflictions resulting from envy and other afflictions? Is there a scientific way to discern this and treat envy without identifying the envier?

The symptoms of the evil eye (al-ayn) and envy (al-hasad) are known to distinguish between them. Symptoms of the evil eye resemble organic diseases that do not respond to medical treatment, such as joint pain, lethargy, insomnia, skin rashes and sores, aversion to family and society, and some neurological and psychological illnesses, in addition to facial pallor, distress, forgetfulness, heaviness in the back of the head and shoulders, tingling in the extremities, body heat, and coldness of the extremities.

As for the symptoms of envy, they appear on one's wealth, body, and children. If envy affects the self, the envied person may suffer from psychological illnesses such as turning away from studying or working, or losing the ability to acquire knowledge, and a decrease in intelligence and memory. They may also tend towards introversion and isolation.

Envy and the evil eye are treated with Ruqyah Shari’ah (Islamic exorcism/incantation), by reciting Surat al-Fatiha, Ayat al-Kursi, the concluding verses of Surat al-Baqarah, Surat al-Qalam (verse 51), Surat al-Ikhlas, and the two Mu'awwidhatayn (Surat al-Falaq and Surat an-Nas), and some prophetic supplications such as: "I seek refuge for you with the perfect words of Allah from every devil and every harmful creature, and from every envious evil eye," and "In the name of Allah, I perform ruqyah for you from everything that harms you, from the evil of every soul, and the eye of an envious person. May Allah cure you. In the name of Allah, I perform ruqyah for you." The ruqyah is recited directly over the patient or over water for them to wash with and drink.

If the person who cast the evil eye is known, they are asked to perform wudu (ablution) or ghusl (ritual bath) so that the afflicted person can wash with the water from their wudu or ghusl, as mentioned in the Prophetic Sunnah.