Short answer
There is no fixed list of signs in the Quran or Sunnah. Magic (sihr) is real and can cause illness or come between a husband and wife, but the same symptoms usually have medical or emotional causes. In the Hanafi school, as in the others, it is haram to diagnose magic by guesswork or to accuse anyone without proof. See a doctor first and keep up ruqyah and the adhkar.
Believing that sihr can harm by Allah's permission is part of Sunni belief. It is haram to diagnose magic by guesswork, to visit a fortune teller or 'amil to find out, or to accuse a person without clear proof. Treating the symptoms with medicine and lawful ruqyah is permitted and encouraged.
The four schools agree on this.
Explanation
The Quran confirms that magic can harm, for example by causing separation between a husband and wife, but only by permission of Allah (2:102). When the Prophet ﷺ was affected by magic, Aishah said he would imagine he had done something when he had not. Beyond that, the Quran and Sunnah give no checklist of symptoms. The lists you find online come from the experience of raqis (people who perform ruqyah), and they are not revelation.
Things people often list include sudden, unexplained hatred between spouses, a strong aversion to prayer or the Quran, frightening dreams night after night, and illness that doctors cannot explain. Every one of these also has common causes: depression, anxiety, marriage problems, sleep disorders, hormonal or neurological conditions. So the first step is always a proper medical check, and a mental health professional where the symptoms are emotional.
What the scholars warn against:
- going to a fortune teller, 'amil or anyone who uses unknown words, numbers or your mother's name to 'diagnose' you
- believing someone who tells you a relative or neighbour has done magic on you, since accusing a Muslim without proof is a serious sin that destroys families
- stopping medical treatment because someone said it is magic
Whatever the cause, these protect and harm nothing: the five prayers, the morning and evening adhkar, Ayat al-Kursi before sleep, Surah al-Baqarah at home, and ruqyah on yourself with al-Fatihah and the last three surahs. The four schools agree on all of this. For treatment, see how to remove black magic, and for the ruling on magic itself, is magic haram.
Ask a mufti about your own case. This answer explains the general ruling. When the details of your situation matter, as they do here, ask a qualified mufti and give them the full facts. Where to ask a scholar.
The evidence
Quran, Surah Al-Baqara 2:102
وَٱتَّبَعُوا۟ مَا تَتْلُوا۟ ٱلشَّيَٰطِينُ عَلَىٰ مُلْكِ سُلَيْمَٰنَ ۖ وَمَا كَفَرَ سُلَيْمَٰنُ وَلَٰكِنَّ ٱلشَّيَٰطِينَ كَفَرُوا۟ يُعَلِّمُونَ ٱلنَّاسَ ٱلسِّحْرَ وَمَآ أُنزِلَ عَلَى ٱلْمَلَكَيْنِ بِبَابِلَ هَٰرُوتَ وَمَٰرُوتَ ۚ وَمَا يُعَلِّمَانِ مِنْ أَحَدٍ حَتَّىٰ يَقُولَآ إِنَّمَا نَحْنُ فِتْنَةٌۭ فَلَا تَكْفُرْ ۖ فَيَتَعَلَّمُونَ مِنْهُمَا مَا يُفَرِّقُونَ بِهِۦ بَيْنَ ٱلْمَرْءِ وَزَوْجِهِۦ ۚ وَمَا هُم بِضَآرِّينَ بِهِۦ مِنْ أَحَدٍ إِلَّا بِإِذْنِ ٱللَّهِ ۚ وَيَتَعَلَّمُونَ مَا يَضُرُّهُمْ وَلَا يَنفَعُهُمْ ۚ وَلَقَدْ عَلِمُوا۟ لَمَنِ ٱشْتَرَىٰهُ مَا لَهُۥ فِى ٱلْءَاخِرَةِ مِنْ خَلَٰقٍۢ ۚ وَلَبِئْسَ مَا شَرَوْا۟ بِهِۦٓ أَنفُسَهُمْ ۚ لَوْ كَانُوا۟ يَعْلَمُونَ ﴿١٠٢﴾
And they followed [instead] what the devils had recited during the reign of Solomon. It was not Solomon who disbelieved, but the devils disbelieved, teaching people magic and that which was revealed to the two angels at Babylon, Harut and Marut. But the two angels do not teach anyone unless they say, "We are a trial, so do not disbelieve [by practicing magic]." And [yet] they learn from them that by which they cause separation between a man and his wife. But they do not harm anyone through it except by permission of Allah. And the people learn what harms them and does not benefit them. But the Children of Israel certainly knew that whoever purchased the magic would not have in the Hereafter any share. And wretched is that for which they sold themselves, if they only knew.
Magic can cause real harm, but only by Allah's permission.
Quran, Surah Al-Hujuraat 49:12
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱجْتَنِبُوا۟ كَثِيرًۭا مِّنَ ٱلظَّنِّ إِنَّ بَعْضَ ٱلظَّنِّ إِثْمٌۭ ۖ وَلَا تَجَسَّسُوا۟ وَلَا يَغْتَب بَّعْضُكُم بَعْضًا ۚ أَيُحِبُّ أَحَدُكُمْ أَن يَأْكُلَ لَحْمَ أَخِيهِ مَيْتًۭا فَكَرِهْتُمُوهُ ۚ وَٱتَّقُوا۟ ٱللَّهَ ۚ إِنَّ ٱللَّهَ تَوَّابٌۭ رَّحِيمٌۭ ﴿١٢﴾
O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy or backbite each other. Would one of you like to eat the flesh of his brother when dead? You would detest it. And fear Allah; indeed, Allah is Accepting of repentance and Merciful.
Suspecting and accusing people of magic without proof falls under forbidden assumption.
Sahih al-Bukhari 5763
Sahih... يخيل إليه أنه يفعل الشىء وما فعله ...
"Aishah said the Messenger of Allah was affected by magic until he would imagine he had done something when he had not."
The one symptom described in the Sunnah, which also shows magic can affect even the best of people.
Sahih Muslim 2230
Sahih... من أتى عرافا فسأله عن شيء لم تقبل له صلاة أربعين ليلة ...
"Whoever goes to a fortune teller and asks him about something, his prayer is not accepted for forty nights."
Seeking a diagnosis of magic from fortune tellers is forbidden.
Where the ruling is recorded
- al-Durr al-Mukhtar, Muqaddimah, on knowledge that is forbidden to learn. Lists sihr and soothsaying among forbidden fields of knowledge.
- Umdat al-Qari (al-Ayni), Kitab al-Tibb, Bab al-Sihr. A Hanafi commentary on the hadith of the Prophet being affected by magic, affirming that magic has real effects.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.