Iselin's disease
Iselin's disease is a cause of pain on the outer edge of the foot in growing children and adolescents. It is caused by irritation of the apophysis, a growth area at the base of the fifth metatarsal. It is more common in active children who run, jump or change direction. Treatment is usually non-surgical, with a temporary reduction of painful activities and a gradual return to sport.
- Typical age
- Roughly between 8 and 13 years of age (pre-adolescence)
- Also known as
- Apophysitis of the fifth metatarsal · Traction apophysitis of the base of the fifth metatarsal
What it is
Iselin’s disease is a traction apophysitis affecting the growth area at the base of the fifth metatarsal, the bone that connects to the little toe, on the outer edge of the foot. This apophysis is a normal part of bone development and is where an important tendon for foot movement and stability attaches: the peroneus brevis tendon.
During growth, the repeated forces transmitted through this tendon, together with the impact of running and jumping, can irritate the apophysis and cause pain. For this reason, the condition is often seen in children who play football, basketball, athletics, gymnastics or other sports that involve running and changing direction.
It is most common in pre-adolescence, while this growth area has not yet fused with the rest of the bone. It may affect only one foot, and the pain usually increases with physical activity, especially after intense training or a recent increase in sports load.
Iselin’s disease is not a fracture in itself and in most cases improves with non-surgical measures. As the skeleton matures and the apophysis closes, the problem usually goes away.
Signs parents may notice
The most common symptoms are:
- Pain on the outer edge of the foot, right on the bony bump at the base of the fifth metatarsal.
- Discomfort when running, jumping, kicking a ball or changing direction.
- Pain when pressing on the area where the peroneus brevis tendon attaches.
- Limping after sport or difficulty carrying on training.
- Mild swelling or local tenderness in some cases.
- Pain that improves with rest and returns when activity starts again.
At first, the child may only notice discomfort during sport. If they keep training through the pain, symptoms may also appear when walking or wearing certain shoes.
When to see a specialist
It is advisable to ask for an assessment by a paediatric orthopaedic specialist when pain on the outer edge of the foot persists, keeps coming back or limits sport.
It is especially important to see a specialist if:
- The child limps or has difficulty putting weight on the foot.
- The pain does not improve after temporarily reducing activity.
- There is marked swelling or very localised pain after an injury.
- The discomfort appears at rest or at night.
- The pain gets gradually worse or stops the child from doing normal activities.
When is it urgent?
If the child cannot put weight on the foot, has severe pain after an injury, or has marked redness, fever or general malaise, they need urgent medical assessment to rule out other causes.
How it is diagnosed
Diagnosis is based on the medical history and physical examination. The specialist identifies the painful spot at the base of the fifth metatarsal, checks tenderness on pressure and assesses foot and ankle movement, as well as how the symptoms relate to sport.
An X-ray may be useful when the diagnosis is uncertain. The normal apophysis of the fifth metatarsal can appear on X-rays as a small separate piece of bone running lengthwise along the bone. In Iselin’s disease, irregularity, fragmentation or changes in the apophysis may be seen, although these findings must be interpreted together with the symptoms and the examination.
It is important to distinguish this condition from a fracture of the base of the fifth metatarsal, which can occur after a twist or an injury, and from other causes of pain on the outer edge of the foot. If the picture is atypical or persists despite treatment, other imaging tests may be needed.
Treatment
Non-surgical treatment
Most children with Iselin’s disease get better without surgery. The aim is to reduce irritation of the apophysis and allow the child to gradually return to normal activity.
1. Temporary reduction of sport
Activities that cause pain should be reduced or stopped for a while, especially running, jumping and changing direction. It is not always necessary to give up all sport: alternative activities that do not cause discomfort can continue.
2. Cold packs
Applying cold, wrapped in a cloth, for about 10–15 minutes after activity can help relieve pain. Ice should never be placed directly on the skin.
3. Suitable footwear
Comfortable shoes with good support and enough room along the outer edge of the foot are recommended, avoiding direct pressure on the painful area.
4. Physiotherapy
When indicated, physiotherapy can help restore ankle movement, improve the flexibility of the leg muscles and work on strength and load control. Exercises should be adapted to the symptoms and should not cause significant pain.
5. Immobilisation in painful cases
If the pain is severe, persists when walking or prevents normal weight-bearing, the specialist may recommend a walking boot for a while. Whether it is needed, and for how long, depends on how severe the symptoms are and on other injuries having been ruled out.
Heel cups or insoles are not routinely needed; they may be considered if there are associated biomechanical problems contributing to the discomfort.
Surgical treatment
Iselin’s disease does not usually require surgery. In the vast majority of cases, the pain goes away with non-surgical treatment and skeletal maturity. Surgery is not indicated for ordinary apophysitis.
If the pain persists for a long time despite appropriate treatment, the diagnosis should be reviewed and other causes ruled out before considering any exceptional procedure.
Outlook and recovery
The outlook is usually very good. Most children improve when painful activities are temporarily reduced and return to sport gradually.
As a general guide:
- First 1–2 weeks: reduce sports load, adapt footwear and use measures to control pain.
- Over the following 2–6 weeks: gradually regain normal walking and tolerance to activity, depending on progress.
- School: the child can usually keep going to school from the start, as long as they can walk comfortably. If they are limping, it may be necessary to reduce walking for a while.
- Back to sport: when the child walks without pain, pressing on the area is painless or only slightly uncomfortable, and they can run, jump and change direction without symptoms during or after activity.
Many cases settle within a few weeks, although discomfort can last several months if the sports overload continues. In the most painful cases, temporary immobilisation and a slower recovery may be needed.
The return to sport should be gradual, increasing duration first and then intensity. If the pain comes back, reduce the load and reassess the progression.
This page is for general information and does not replace an assessment by a specialist. If you are worried about your child's foot, talk to their paediatrician or book an appointment.