Like all medicines, betamethasone can cause side effects in some people, but many people have no side effects or only minor ones.
Side effects are unlikely if you follow the instructions that come with your medicine.
You're more likely to have side effects if you use it on large areas of skin for a long time, or on sensitive skin areas such as your face, or under dressings or nappies.
Mild side effects
Some people get a burning or stinging feeling for a few minutes when they put betamethasone on their skin. This stops happening after you've been using it for a few days.
If you get lighter or darker patches on your skin (this may be more difficult to see on brown or black skin) these are a sign of changes to the pigment in your skin. Speak to your doctor if this happens.
Speak to a doctor if your condition gets worse while you're using betamethasone skin treatments, or comes back within 2 weeks of stopping treatment. Do not start using beclomethasone again without speaking to a doctor.
Serious side effects
Serious side effects are rare. They happen to less than 1 in 10,000 people who use betamethasone skin treatments. You're more likely to have a serious side effect if you use betamethasone on a large area of skin for a long time.
Using betamethasone for a long time can make your skin thinner or cause stretch marks. Stretch marks are likely to be permanent, but they usually fade over time.
Call a doctor or call 111 and stop using betamethasone straight away if:
- your skin becomes swollen, yellow fluid is weeping from your skin or your skin becomes redder (redness may be less obvious on brown or black skin) – these are signs of a new skin infection or an existing one getting worse
- you're using betamethasone for psoriasis and you get raised bumps filled with pus under your skin
- you have a very upset stomach or you're being sick (vomiting), you feel very tired or very dizzy or start to faint, you get muscle weakness, have mood changes, loss of appetite and weight loss – these can be signs of adrenal gland problems
- you feel confused, sleepy, more thirsty or hungry than usual, pee more often, start breathing quickly or your breath smells of fruit – these can be signs of high blood sugar (hyperglycaemia)
- you have any new problems with your eyesight after starting to use betamethasone
Serious allergic reaction
It happens rarely, but it's possible to have a serious allergic reaction (anaphylaxis) to betamethasone.
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Long-term side effects
Using betamethasone for a long time without stopping can mean some of the medicine gets into your blood.
If this happens, there's a very small chance it can cause serious side effects, such as adrenal gland problems, high blood sugar (hyperglycaemia), or problems with your eyesight.
If you've been using betamethasone for a long time, your doctor may tell you to gradually reduce the amount you use before stopping completely.
If you've been using betamethasone for a long time, you may have a skin reaction within a few days or weeks after stopping treatment (topical steroid withdrawal reaction). You might have a burning feeling and redness, although this may be more difficult to see on brown or black skin. If this happens, ask your doctor for advice.
Long-term side effects in children and teenagers
In very rare cases, using betamethasone skin treatments for a long time can slow the normal growth of children and teenagers.
Your child's doctor will monitor their height and weight carefully if they need to use this medicine often. This will help them to notice if your child's growth is being affected and they can change the treatment if needed.
Even if your child's growth slows down, it does not seem to have much effect on their eventual adult height.
Talk to your doctor if you're worried. They'll be able to explain the benefits and risks of your child using betamethasone.
Other side effects
These are not all the side effects of betamethasone. For a full list, see the leaflet inside your medicine packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.