Most people notice it suddenly, one ordinary day -
not from anything dramatic, but from a completely everyday movement: turning a tap, wringing out a towel, picking up a child, lifting a coffee cup - and a stab of pain shoots through the base of the thumb, sharp enough to stop you for a second.
It isn't a sprain and it isn't a knock. There's no obvious reason for it. But it's there every day, and it's happening more often.
If that sounds familiar, this article is for you.
"Mummy thumb" isn't only for mothers
The formal name is De Quervain's tenosynovitis, affecting the two tendons running from the base of the thumb along the thumb side of the wrist. When those tendons are overused and rub repeatedly over long periods, the sheath around them becomes inflamed and swollen - so every thumb movement feels like pulling on a rope that's already frayed.
Despite the nickname, all of these groups are prone to it:
New parents: dozens of times a day lifting a baby, supporting its head, changing nappies - the force through the thumb is far greater than you'd imagine.
Heavy phone users: holding the phone one-handed with the thumb constantly swiping is one of the most common modern causes. Research suggests the risk rises significantly above about 4 hours of phone use a day.
Anyone running a household: wringing towels, chopping, mopping, twisting bottle caps - these look undemanding, but the cumulative wear on the thumb tendons is remarkable.
Hairdressers, massage therapists, chefs: occupations applying force through the thumb for hours are high risk.
Women around the menopause: hormonal change can affect tendon elasticity and tolerance, making tendon problems of all kinds more likely at this stage.
How do you know it's De Quervain's? Try this test
There's a simple self-test, known medically as the Finkelstein test:
- Tuck your thumb into your palm and close your other four fingers over it
- Bend the wrist towards the little-finger side (downward)
- If that movement produces clear stabbing pain from the base of the thumb into the wrist - you very likely have De Quervain's.
Other common symptoms: swelling at the base of the thumb, pain when pressed, marked stiffness first thing in the morning, and pain that worsens when pinching or twisting.
Does it resolve on its own?
Mild cases can ease with proper rest and the support of a brace.
The key phrase is genuine rest - not simply using your phone a bit less, but actually letting the inflamed tendon stop.
The difficulty is that the thumb is involved in almost every hand movement, so avoiding it entirely in daily life is close to impossible. That's exactly why a thumb brace matters at this stage - it isn't a treatment, it's a way to physically limit particular thumb movements, giving the tendon the breathing space it needs while you carry on with your life.
If symptoms last more than six weeks, or the pain affects daily life, get assessed. A doctor may suggest anti-inflammatory medication or a steroid injection, and severe cases may need surgery.
How to choose a brace: 3 things that matter
There are plenty of wrist braces out there, but De Quervain's doesn't need a general sports brace - it needs one with a thumb-stabilising design.
1. A thumb loop or thumb stay. This is the critical feature. A standard brace only wraps the wrist, but the problem here is the tendons at the base of the thumb, so the thumb has to be stabilised too for friction and inflammation to actually reduce.
2. Adjustable support strength. The acute inflammatory phase needs firmer immobilisation; once symptoms improve, everyday use calls for something lighter with more freedom of movement. A design with adjustable hook-and-loop fastenings lets you set it to the day.
3. Comfort for everyday wear. A brace for De Quervain's needs to be worn as much of the day as possible, and if the material is heavy or airless you simply won't want to. Choose a light, breathable stretch fabric - that's what makes continuous protection realistic.
Beyond the brace, these matter too
Change how you hold your phone: swipe with your index finger instead of your thumb, or use a stand to cut down holding time.
Change how you lift a baby: avoid supporting the baby on the thumb alone - use the whole palm and forearm to spread the load.
Do this stretch three times a day: open the thumb outward, hold 15 seconds, release. Repeat 10 times. It helps the tendon regain suppleness - but skip it during acute painful inflammation and start once the pain settles.
Cold first: in the acute phase (clear redness, swelling, warmth and pain) use cold, 15-20 minutes at a time. Switch to heat for circulation only once the pain has become chronic.
Related reading
- Trigger finger: how finger splints work, explained by a physiotherapist
- Neck and shoulder pain: 5 ways to ease it for desk workers
Frequently asked questions
Q1: Do I have to see a doctor? Mild symptoms can be watched with rest, a brace and cold therapy. But if pain lasts more than 4-6 weeks, or affects daily life (it hurts even to pick up a cup), get a diagnosis and have other causes ruled out.
Q2: How long until a brace helps? Mild cases with the right brace and fewer aggravating movements usually improve noticeably within 4-8 weeks. But everyone differs - judge by whether symptoms are easing rather than by a fixed timeline.
Q3: Do I need to wear it to sleep? If you tend to bend your wrist unconsciously while asleep, wearing it overnight can help. Choose a lighter, breathable design so your sleep isn't disturbed.
Q4: Can it come back after it's healed? Yes. Without changing the movement habits that triggered it, the recurrence rate is high. Even after recovery, wearing a brace during high-risk activity and keeping up hand stretches is worth doing.
Q5: Do steroid injections work? They're effective for moderate cases, and one injection often gives several months of relief. But an injection isn't a cure - if the underlying trigger hasn't changed, it can still return. Discuss with your doctor whether it suits you.
