What's dermatomyositis?
Dermatomyositis is an idiopathic inflammatory myopathy: an autoimmune disease of muscle and skin. Classic features are symmetric proximal muscle weakness, the pathognomonic Gottron's papules and sign and heliotrope rash, elevated creatine kinase, and myositis-specific autoantibodies (such as anti-Mi-2, anti-MDA5, anti-TIF1-γ), with interstitial lung disease an important complication. Distinct subtypes include clinically amyopathic dermatomyositis, a juvenile form, and a cancer-associated form, which differ in scope from classic adult disease. First-line treatment is systemic glucocorticoids, with steroid-sparing immunosuppressants (methotrexate, azathioprine, mycophenolate), intravenous immunoglobulin, and rituximab used as needed.
| Also indexed as | ORPHA:221, MONDO:0016367 |
|---|---|
| Features mapped | 16 |
| Treatments mapped | 8 |
| Published sources | 14 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Shawl sign
The shawl sign is a reddish rash spread across the back of the shoulders, upper back, and the back of the neck — the area a shawl would cover. It is one of the photosensitive rashes seen in dermatomyositis.
V-sign
The V-sign is a reddish, sometimes itchy rash across the front of the neck and upper chest in a V shape, in sun-exposed skin. It is one of the characteristic dermatomyositis rashes, alongside the heliotrope rash and Gottron's papules.
Abnormal pulmonary interstitial morphology
Interstitial lung disease, inflammation and scarring of the lung tissue, is an important complication. It can cause breathlessness and cough and is a major driver of how serious the disease becomes, so lung function is monitored.
Gottron's papules
Gottron's papules are raised, reddish or violet bumps over the knuckles and other finger joints. They are one of the most common and most recognizable skin signs of dermatomyositis.
Abnormal nail morphology
The tiny blood vessels at the base of the fingernails (nailfold capillaries) can become abnormal in dermatomyositis — thinned out, enlarged into "giant" loops, or surrounded by swelling. These changes tend to be more pronounced when the disease is active.
Gottron sign
The Gottron sign is a flat, reddish or violet patch over the joints — most often the knuckles, elbows, or knees — without the raised bump seen in Gottron's papules. It is one of the characteristic skin findings of dermatomyositis.
Neoplasm
Dermatomyositis carries a meaningfully higher risk of cancer than the general population, and in a substantial share of adults the disease is paraneoplastic, meaning it is triggered by an underlying tumor. Because of this, a new diagnosis usually prompts age-appropriate cancer screening.
Anti-Mi2 antibody positivity
Anti-Mi-2 is one of the dermatomyositis-specific autoantibodies. Like anti-TIF1-gamma and anti-MDA5, it marks a particular subtype of dermatomyositis, which can help with diagnosis and with anticipating how the disease may behave.
Anti-MDA5 antibody positivity
Anti-MDA5 is another myositis-specific autoantibody. It marks a subtype that often has little muscle weakness but a high risk of rapidly progressive interstitial lung disease, so its detection changes how closely the lungs are watched.
Heliotrope rash
A heliotrope rash is a violet or dusky discoloration of the eyelids, sometimes with swelling. It is one of the hallmark skin signs and points strongly to the diagnosis.
Anti-transcription intermediary factor-1gamma antibody positivity
Anti-TIF1-gamma is one of the dermatomyositis-specific autoantibodies. In adults it is strongly linked to cancer-associated disease, so a positive result raises the priority of looking for an underlying malignancy.
Elevated circulating creatine kinase activity
Creatine kinase is an enzyme that leaks into the blood when muscle is being damaged. A raised creatine kinase level can be a sign of the muscle inflammation that occurs in dermatomyositis.
Proximal muscle weakness
Dermatomyositis often causes weakness of the proximal muscles — the ones closest to the trunk, such as the hips, thighs, shoulders, and upper arms. This can make it hard to climb stairs, rise from a chair, or lift the arms overhead. It is one of the defining features of the disease, alongside the characteristic skin rashes.
Dysphagia
Dysphagia means difficulty swallowing. In dermatomyositis it can happen when the muscles involved in swallowing become inflamed and weak, and it is one of the clinical features that can occur in the disease.
Dysphonia
Dysphonia means a change in the voice, such as hoarseness. In dermatomyositis it can come from inflammation affecting the muscles of the voice box, and it may be an early or easily overlooked feature.
Calcinosis cutis
Some people with dermatomyositis develop hard calcium deposits under the skin (calcinosis cutis), which can be painful, break through the skin, or limit movement. It is most common in children with the juvenile form but can also occur in adults.
How it is diagnosed
Dermatomyositis
Diagnosed using: electromyography (EMG).
“Electromyography is valuable in identifying mild myopathy among DM patients with subtle clinical muscle weakness, allowing better classification of DM subtypes.”
Dermatomyositis
Diagnosed using: myositis-specific autoantibody testing.
“Immunologic testing reveals myositis-specific autoantibodies that associate with characteristic clinical patterns, pattern of organ involvement, and prognostic implications, including interstitial lung disease and malignancy.”
Dermatomyositis
Diagnosed using: muscle biopsy.
“The absence of definitive serologic markers in all cases of dermatomyositis requires a comprehensive diagnostic approach integrating clinical features, supportive testing, and histopathologic evaluation in dermatomyositis.”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
glucocorticoids
Glucocorticoids (corticosteroids such as prednisone) are the first-line treatment. They suppress the immune attack and usually improve both the muscle and skin disease, after which the dose is slowly reduced.
Used to help with: Dermatomyositis.
“All patients were treated with glucocorticoids and received different immunosuppressants, including cyclophosphamide.”
rituximab
Rituximab is a targeted antibody medicine that depletes the B-cells driving the immune attack. It is used for disease that does not respond to first-line treatment, and sometimes earlier in severe cases.
Used to help with: Dermatomyositis.
“The patient responded well to pulse steroids, intravenous immunoglobulin, and rituximab, achieving remission and successfully tapering off corticosteroids.”
systemic glucocorticoids
Systemic glucocorticoids (steroids taken by mouth or by vein) are a mainstay of dermatomyositis treatment, used to calm the immune attack on the muscles and skin. They are typically combined with other immune-suppressing medicines and, in some cases, intravenous immunoglobulin.
Used to help with: Dermatomyositis.
“Current management approaches include systemic glucocorticoids, conventional and emerging immunosuppressive therapies, and intravenous immunoglobulin.”
methotrexate
Methotrexate is an immune-suppressing medicine used in dermatomyositis. In this cohort, which included people with dermatomyositis, it was given alongside glucocorticoids to bring the disease under control and was also used as a longer-term maintenance treatment.
Used to help with: Dermatomyositis.
“Glucocorticoids (GCSs) were administered in all patients for induction in addition to cyclophosphamide (28.6%), mycophenolate mofetil (MMF) (51.4%), and methotrexate (MTX) (17.1%).”
azathioprine
Azathioprine is an immune-suppressing medicine used as a maintenance treatment in dermatomyositis — taken over the longer term to keep the disease quiet after it is brought under control. In this cohort, which included people with dermatomyositis, it was one of the more frequently used maintenance options.
Used to help with: Dermatomyositis.
“Maintenance therapy included MTX (20%), MMF (31.4%), rituximab (34.3%), azathioprine (AZA) (42.9%), and others.”
antimalarials (hydroxychloroquine)
Antimalarial medicines such as hydroxychloroquine are part of the conventional treatment of dermatomyositis, used especially for the skin disease. Even so, some cases of chronic skin involvement do not fully respond and need additional therapy.
Used to help with: Dermatomyositis.
“While conventional immunosuppressive therapies like glucocorticoids and antimalarials form the cornerstone of treatment, many cases remain refractory, particularly involving chronic skin disease.”
intravenous immunoglobulin (IVIG)
Intravenous immunoglobulin (IVIG) is a preparation of pooled antibodies given by vein. It is one of the treatments used in dermatomyositis, alongside glucocorticoids and other immune-suppressing therapies.
Used to help with: Dermatomyositis.
“Current management approaches include systemic glucocorticoids, conventional and emerging immunosuppressive therapies, and intravenous immunoglobulin.”
mycophenolate mofetil
Mycophenolate mofetil is an immune-suppressing medicine used in dermatomyositis. In this cohort, which included people with dermatomyositis, it was used both alongside glucocorticoids early on and as a maintenance treatment.
Used to help with: Dermatomyositis.
“Glucocorticoids (GCSs) were administered in all patients for induction in addition to cyclophosphamide (28.6%), mycophenolate mofetil (MMF) (51.4%), and methotrexate (MTX) (17.1%).”
What changes how it shows up
The diagnosis is not the whole story. The factors and open questions below are described in the research mapped here as shaping whether, or how strongly, the condition shows up, or as points the field has not yet settled. They are not, on their own, its cause or its cure.
anti-MDA5 antibody (interstitial lung disease risk)
In anti-MDA5 antibody-positive dermatomyositis, the disease tends to produce characteristic skin changes, blood-vessel damage, and a high rate of rapidly progressive interstitial lung disease — lung scarring that can worsen quickly. This makes the lungs a particular concern in this subtype.
Described as modulating: Dermatomyositis.
“These immune abnormalities result in characteristic cutaneous manifestations, vasculopathy, and a high prevalence of rapidly progressive interstitial lung disease.”
malignancy association (anti-TIF1-gamma)
Dermatomyositis with the anti-TIF1-gamma antibody is strongly linked to cancer: in a literature review of these patients, malignancy was found in about 43%. Because of this, a positive anti-TIF1-gamma result raises the priority of looking for an underlying cancer.
Described as modulating: Dermatomyositis.
“Prevalence of malignancy was 42.6% among patients with Anti TIF1-γ.”
How to read the evidence labels
Where this comes from
This guide is built from 14 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.