Inflammatory myopathies (myositis)

Inflammatory myopathies are autoimmune conditions: the immune system, which normally fights infection, mistakenly attacks the muscles, causing the inflammation that leads to weakness. In polymyositis the inflammation sits within the muscle fibres themselves, while in dermatomyositis it also affects the small blood vessels supplying the muscle and skin, which is why skin changes appear. Why this happens is usually not known, and it is not something you have caused or could have prevented.

They can affect any age but tend to appear in adulthood, and are a little more common in women. They sometimes occur alongside other autoimmune conditions such as lupus or systemic sclerosis, part of the wider family of connective tissue disease. In dermatomyositis particularly, an underlying cancer is occasionally found, which is why careful assessment sometimes includes screening tests.

The hallmark is muscle weakness, usually developing over weeks to months. Features may include:

• Weakness of the larger muscles, such as the thighs, hips and shoulders
• Difficulty with actions like climbing stairs, rising from a chair, or lifting the arms
• Muscle aching or tenderness in some people
• In dermatomyositis, characteristic skin changes alongside the muscle symptoms
• Sometimes tiredness, or effects on other systems

Diagnosis brings together your symptoms, an examination, blood tests including muscle enzymes and particular antibodies, and further investigations such as scans or muscle studies. Because several conditions can cause muscle weakness, a thorough assessment is important to confirm the diagnosis.

Where the joints are involved, ultrasound can help assess inflammation. Dr Borukhson uses point-of-care ultrasound during the consultation. You can read more on the ultrasound clinic page.

Treatment aims to calm the immune-driven inflammation, restore and protect muscle strength, and manage any other affected areas. Corticosteroids, usually prednisolone, are often used first to bring the inflammation under control. A steroid-sparing immunosuppressant such as methotrexate, azathioprine or mycophenolate is often added so the steroid dose can be reduced over time, and in selected cases immunoglobulin (IVIG), given by infusion, may also have a role. All of these are used under specialist supervision and discussed fully with you.

These medicines need some care: longer steroid courses call for bone protection and monitoring, and immunosuppressants need regular blood tests and can increase the risk of infection. Treatment is tailored to the individual and reviewed over time, often alongside physiotherapy to support recovery of strength. The plan is agreed with you.

The heart is a muscle too, and occasionally the same inflammation that causes weakness in the limbs can involve the heart muscle itself (myocarditis) or the heart's rhythm. Left untreated, that inflammation can weaken the heart over time. If you notice new breathlessness, palpitations or tiredness out of proportion to the muscle symptoms, tell your team promptly rather than putting it down to the condition. Where the heart does need attention, care is shared with cardiology, and good control of the underlying inflammation protects the heart as well as the muscles. Regular heart-health checks are also part of looking after myositis, as with other inflammatory conditions. Our guide to inflammation and your heart explains why, and which checks are worth asking about.

Inflammatory muscle disease can involve more than the muscles alone, so care sometimes needs input from more than one specialty. Dr Borukhson practises within a world-renowned tertiary centre, with ready access to consultant colleagues across the other specialties that may be involved in caring for this condition. Where appropriate, she can involve those specialists directly, and bring particularly complex cases to a multidisciplinary team meeting (MDT) with minimal delay. This means that, when more than one area of expertise is needed, your care can be joined up and decisions reached promptly.

Recovery is gradual, and the most helpful thing you can do is pace your activity while strength returns. Follow the exercises your physiotherapist sets rather than pushing through fatigue, and rest when you need to; gentle, regular movement rebuilds muscle more reliably than occasional heavy effort.

A few measures support treatment:

• Protect your skin from the sun if you have dermatomyositis, as light can aggravate the rash
• Eat well and stay active within your limits to help protect bone and muscle while on steroids
• Keep up routine vaccinations before or during immunosuppression, as advised by your team
• Report any infection early, since the medicines can blunt your usual response

Many people regain useful strength and return to their everyday activities. Staying in touch between appointments helps the plan keep pace with how you are doing.

Some symptoms need prompt, same-day attention rather than waiting for your next appointment. Seek urgent help if you develop:

• Difficulty breathing or unusual breathlessness, which can reflect involvement of the chest or lungs or, less often, the heart
• Chest pain or new palpitations; call 999 immediately if chest pain is crushing, tight or pressure-like, spreads to an arm, the jaw, the neck or the back, or comes with breathlessness, sweating or feeling sick
• Trouble swallowing, choking, or food and drink going the wrong way
• A fever or feeling generally unwell while taking immunosuppressants, as infection needs early treatment
• A rapid worsening of weakness, or new falls

Contact your specialist team for a routine review, rather than emergency care, if weakness is slowly returning, new skin changes appear, tiredness feels out of proportion to your muscle symptoms, or you are struggling with side effects from the medicines. When you are unsure how urgent something is, it is always reasonable to ask. Quick assessment of these warning signs helps keep treatment safe and on track.

Recognising and treating inflammatory muscle disease early helps preserve strength and function. If you have developing muscle weakness that affects everyday movements, particularly climbing stairs or rising from a chair, a specialist review is worthwhile.

How are inflammatory myopathies diagnosed?

Because muscle weakness has many possible causes, the diagnosis brings several things together rather than resting on a single test. Dr Borukhson assesses your symptoms and examines your muscle strength, then arranges blood tests for muscle enzymes and specific antibodies, alongside further investigations such as scans or muscle studies where needed. Where the joints are involved, point-of-care ultrasound during the consultation can help assess inflammation, so much of the picture is built up in one visit.

How is myositis treated, and how long does treatment last?

Treatment aims to calm the immune-driven inflammation and protect muscle strength. A corticosteroid, usually prednisolone, is often started first to bring things under control, with a steroid-sparing immunosuppressant such as methotrexate, azathioprine or mycophenolate added so the steroid dose can be lowered over time. Physiotherapy supports recovery of strength. This is usually a longer-term plan, reviewed regularly and adjusted to how you respond, rather than a fixed short course.

What can I expect for recovery, and will my strength come back?

Many people regain useful strength once the inflammation is controlled, and treating the condition early helps preserve muscle and function. Recovery tends to be gradual rather than sudden, and physiotherapy has an important role in rebuilding strength safely. Progress varies from person to person, so the plan is reviewed over time and tailored to you. Staying in touch with the team and attending monitoring appointments helps keep things on track.

Are there side effects from the medicines, and what monitoring is needed?

These medicines are effective but need some care. Longer steroid courses call for bone protection and monitoring, and immunosuppressants need regular blood tests and can increase the risk of infection, so any new fever or feeling unwell is worth reporting promptly. The monitoring is there precisely to use these treatments safely. Everything is supervised by the specialist and discussed fully with you before starting.

Can myositis affect the heart?

Occasionally, yes. The heart is a muscle too, and the same inflammation that weakens the limbs can involve the heart muscle (myocarditis) or the heart's rhythm. Because untreated inflammation can weaken the heart over time, let your team know promptly about any new breathlessness, palpitations or tiredness that feels out of proportion to your muscle symptoms, rather than putting it down to the myositis. Heart health is also checked regularly as part of your care, cardiology joins the team where the heart needs attention, and keeping the inflammation well controlled protects the heart as well as the muscles.

When should I seek a specialist review for muscle weakness?

It is worth seeking review if you develop weakness in the larger muscles that affects everyday actions, such as climbing stairs, rising from a chair or lifting your arms above your head, particularly when it builds up over weeks rather than after a single strenuous day. New skin changes alongside muscle symptoms, or any difficulty with breathing or swallowing, warrant prompt attention. Recognising and treating the condition early helps protect strength and function.