There are two veins
Al-Kāfi|Volume 8|Book 1|Chapter 578
مُحَمَّدُ بْنُ يَحْيَى عَنْ مُوسَى بْنِ الْحَسَنِ عَنْ مُحَمَّدِ بْنِ عَبْدِ الْحَمِيدِ بِإِسْنَادِهِ رَفَعَهُ إِلَى أَبِي عَبْدِ اللَّهِ (عليه السلام) قَالَ قَالَ رَسُولُ اللَّهِ (صلى الله عليه وآله) مَا مِنْ أَحَدٍ مِنْ وُلْدِ آدَمَ إِلَّا وَ فِيهِ عِرْقَانِ عِرْقٌ فِي رَأْسِهِ يُهَيِّجُ الْجُذَامَ وَ عِرْقٌ فِي بَدَنِهِ يُهَيِّجُ الْبَرَصَ فَإِذَا هَاجَ الْعِرْقُ الَّذِي فِي الرَّأْسِ سَلَّطَ اللَّهُ عَزَّ وَ جَلَّ عَلَيْهِ الزُّكَامَ حَتَّى يَسِيلَ مَا فِيهِ مِنَ الدَّاءِ وَ إِذَا هَاجَ الْعِرْقُ الَّذِي فِي الْجَسَدِ سَلَّطَ اللَّهُ عَلَيْهِ الدَّمَامِيلَ حَتَّى يَسِيلَ مَا فِيهِ مِنَ الدَّاءِ فَإِذَا رَأَى أَحَدُكُمْ بِهِ زُكَاماً وَ دَمَامِيلَ فَلْيَحْمَدِ اللَّهَ عَزَّ وَ جَلَّ عَلَى الْعَافِيَةِ وَ قَالَ الزُّكَامُ فُضُولٌ فِي الرَّأْسِ.
579. Muhammad Bin Yahya, from Muhas Bin Al-Hassan, from Muhammad Bin Abdul Hameed, by his unbroken chain going up to Abu Abdullah عليه الصلاة والسلام, the following: Abu Abdullah عليه الصلاة والسلام has said: ‘The Rasool Allah صلى الله عليه وعلى آله وسلم said: ‘There is no one from the children of Adam عليه السلام except that there are two veins within him. A vein in his head which incites the leprosy, and a vein in his body which incites the vitiligo. So if the vein in the head gets incited, Allah عز وجل Mighty and Majestic Makes the flu to overcome it until the illness flows out from it. And if the vein which is in the body gets incited, Allah عز وجل Makes it to be overcome by the abscesses until the illness flows out from it. So if one of you sees the flu and abscesses, so he should Praise Allah عز وجل Mighty and Majestic for the health’. And he عليه الصلاة والسلام said; ‘Flu has origin in the head’.
- Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (16/583)
- Ṣaḥīḥ al-Kāfī