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Paresis nervi facialis
Does the forehead still move? If it stays mobile and only the mouth droops, it is an emergency in the head — and for the rest, three days and protecting the eye decide.
Also known as: facial palsy · Bell’s palsy · drooping mouth corner
Open in the tool — with search and all the links →This compilation is for information and replaces neither medical diagnosis nor treatment. If you have symptoms, see a doctor.
A sudden weakness of the facial muscles on one side is always a reason to be seen at once — and there is one distinction anyone can make in seconds. It runs: does the forehead still move? In the harmless, common form the whole half of the face is affected, the forehead cannot be wrinkled and the eye cannot be closed. If the forehead by contrast stays mobile and only the corner of the mouth droops, that points to the brain — and thus to a stroke, where every minute counts. The common form is called Bell’s palsy; it arises from swelling of the facial nerve in its narrow bony canal and recovers largely in most cases. Two things decide the outcome. First the timing: a course of cortisone works best when it begins within three days. Second the eye — if the lid does not close, the cornea dries out, and that is the one lasting damage that can reliably be prevented. Other causes are looked for when it occurs on both sides, develops over weeks, follows a tick bite, or when blisters appear in the ear. If hearing loss, ringing in the ears, altered sensation in the face or double vision are added, that speaks against the ordinary form and for another cause that needs clarifying.
As long as it is not certain whether the forehead is involved, the suspicion of a stroke stands. That suspicion alone justifies the emergency call — nothing is lost if it is not confirmed.
In Bell’s palsy a short course of cortisone clearly improves the outlook when it starts early. That is why one does not wait over the weekend.
By day drops without preservative, every one to two hours; at night an ointment and the lid held loosely closed with a strip of tape, or a moisture chamber. This is the one measure that prevents lasting damage.
Especially in children, in summer and with palsy on both sides. Lyme disease as a cause is treated differently, and the question costs nothing.
Gentle, deliberate movements in front of a mirror with speech or physiotherapy guidance help. Strong electrical stimulation is not recommended, because it can encourage unwanted co-movements.
Food collects in the paralysed cheek, drinks run from the corner of the mouth. Small mouthfuls, a thicker consistency and mouth care after eating save a lot of trouble.
In Bell’s palsy the weakness reaches its peak within seventy-two hours. Cortisone works if it is started within the first seventy-two hours — barely later; that is the most important moment of the whole illness. About seven out of ten people recover fully, more than eight out of ten with cortisone. Recovery runs over three to six months. The eye needs protection during that time, because the lid does not close.
Cortisone works in Bell’s palsy — but only if started within the first seventy-two hours; that is the most important moment of the whole illness. Antivirals add little and are given only in severe forms. What no drug does is protect the eye: without lid closure it needs drops by day, ointment and a dressing at night — otherwise the cornea dries out, and that is the damage that stays.
When one half of the face does not join in, the people around read feelings that are not there — or miss ones that are. That belongs considered for as long as it lasts.
That is the one sign that justifies calling for help. If only the corner of the mouth droops and the forehead can still be wrinkled, the cause lies in the brain.
The most important practical point of the whole illness. Without lid closure the cornea dries out, and that is where the one damage that can remain comes from.
That speaks for shingles on the facial nerve. It hurts more, recovers less well and is also treated against the virus — which is why looking in the ear is worthwhile.
Both accompany the same nerve and tell the examination at what level the damage sits. They are unpleasant but not a bad sign.
Bell’s palsy is complete within hours to two days. A slowly increasing weakness does not fit and needs imaging.
In children, with palsy on both sides, after a tick bite or after a spreading rash this value belongs alongside — the treatment is then a different one.
Diabetes is commoner with this palsy, delays recovery and is also the reason a course of cortisone is followed more closely.
Not for the diagnosis but for the exceptions: an infection in the ear, Lyme disease or a rare inflammatory illness in the background.
Without B12 the insulating layer of the nerves is not maintained. A lack causes tingling, numbness and unsteadiness in the dark — and it is one of the few reasons for nerve trouble that can be fully undone if found early.
The nerves cover their energy needs through thiamine. It runs short with alcohol, after stomach operations, with long-lasting vomiting and under water tablets.
Here both count: a lack harms the nerves, and too high an intake over months harms them as well. Supplements therefore belong taken in a dose that has a reason.
Works together with B12. Given alone, folate can improve the blood count while the B12 deficiency goes on damaging the nerves — which is why both are looked at together.
Treatment of sudden facial palsy runs through cortisone, and the earlier it begins the better — within 72 hours is the frame. Over those few days bone is not a topic; it becomes one only if cortisone is repeated or given for longer.
In some small studies B12 was given in addition, with inconsistent results. What reliably counts is something else: the eye. If the lid does not close, the cornea dries out, and the lasting damage arises there — not at the nerve.
In pregnancy clearly established against neural-tube defects, otherwise mainly with deficiency. Can mask a B12 deficiency — watch both.
In the idiopathic form cortisone is the treatment with the best numbers — started within 72 hours. After that the benefit falls markedly; here the clock decides more than the dose.
With diabetes it occurs several times more often and heals less well. At the same time the cortisone raises the sugar — with diabetes it belongs measured more often in those days, not less.
In pregnancy, especially in the last third and just after birth, it occurs about three times more often. The reason is probably the water retention in the nerve’s narrow canal.
Food gathers in the paralysed cheek and escapes from the corner of the mouth. Softer food, smaller bites and drinking through a straw help through the weeks until strength returns.
Targeted exercises with a mirror support recovery. Vigorous training in the early phase can encourage unwanted co-movements — hence gentle and guided, not forced.
Warmth eases the tightness. The eye needs more attention than the face in this time — without lid closure the cornea dries out.
AWMF 030-013 · S2k · 2022-05 — in force
Therapie der idiopathischen Fazialisparese (Bell’s palsy)
checked 2026-09