Is shaving the head permissible?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Shaving the head is of four kinds:

Firstly, shaving the head during Hajj and ‘Umrah. This is permitted by the Word of Allah, His Prophet and the consensus of the Muslim nation; so, it is recommended. Allah Says (what means): {…You will surely enter al-Masjid al-Haram, if Allah wills, in safety, with your heads shaved and (some having his) [hair] shortened, not fearing [anyone]} [Quran 48:27]

Secondly, shaving the head for medical reasons: This is also permitted in the Sharee’ah. Allah permitted the one who is in the state of Ihram to shave his head when he faces problems, even though shaving during the state of Ihram is forbidden. Allah Says (what means): {… And whosoever of you is ill or has an ailment in his scalp (necessitating shaving), he must pay a Fidyah (ransom) of either observing Saum (fasts) (three days) or giving Sadaqah (charity - feeding six poor persons) or offering sacrifice (one sheep)…..} [Quran 2:196]. Also, it is reported that Ka'b said: "The Prophet came to me at the time of Al-Hudaybiyah while lice were falling on my face. He said, "Are the lice of your head troubling you?" I said, "Yes". He said, "Shave your head and fast for three days, or feed six poor persons, or slaughter a sheep as sacrifice". [Al-Bukhari and Muslim]

Thirdly, shaving the head as a religious rite, or to show asceticism, or to make it as a special sign to be known by, etc. this is an innovation and consequently not permissible in the Sharee’ah. It was a sign of the Khawarij; as narrated in Al-Bukhari that the Prophet said: ''Some people will emerge from the East who will recite the Quran but it will not exceed their throats; they will renounce the religion (i.e. they will abandon the obedience of the Islamic leader) in the same way as an arrow passes through the game, and they will never come back to it unless the arrow, comes back to the middle of the bow (by itself) (i.e. impossible). The people asked, "What will their signs be?" He said, "Their sign will be the habit of shaving ".

Fourthly, shaving the head for other than for Hajj or Umrah and without considering it a religious act; the Muslim scholars have two opinions whether or not this permissible. Imam Maalik and his followers say that it is disliked, while the followers of Imam Abu Haneefah and Shafi’i believe that it is permissible. The latter opinion is correct since the Prophet saw a child with half of his head shaved and other half of his head was left unshaved, then he said: "Either shave his head completely or leave it completely unshaved". [Abu Dawood, An-Nassa’i, and Ibn Habban]

Allah knows best.