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Dermatomyositis

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Dermatomyositis
Discrete redareasoverlying theknucklesin a person with juvenile dermatomyositis. These are known as Gottron's papules.
SpecialtyRheumatology
SymptomsRash, muscle weakness, weight loss, fever[1]
ComplicationsCalcinosis,lung inflammation,heart disease[1][2]
Usual onset40s to 50s[3]
DurationLong term[1]
CausesUnknown[1]
Diagnostic methodBased on symptoms, blood tests,electromyography,muscle biopsies[3]
Differential diagnosisPolymyositis,inclusion body myositis,scleroderma[3]
TreatmentMedication,physical therapy,exercise, heat therapy,orthotics,assistive devices, rest[1]
MedicationCorticosteroids,methotrexate,azathioprine[1]
Frequency~ 1 per 100,000 people per year[3]

Dermatomyositis(DM) is along-terminflammatory disorderwhich affects theskinand themuscles.[1]Its symptoms are generally askin rashand worsening muscle weakness over time.[1]These may occur suddenly or develop over months.[1]Other symptoms may include weight loss, fever, lung inflammation, or light sensitivity.[1]Complications may includecalcium deposits in muscles or skin.[1]

The cause is unknown.[1]Theories include that it is anautoimmune diseaseor a result of aviral infection.[1]Dermatomyositis may develop as a paraneoplastic syndrome associated with several forms of malignancy.[4]It is a type ofinflammatory myopathy.[1]Diagnosis is typically based on some combination of symptoms, blood tests,electromyography,andmuscle biopsies.[3]

Eighty percent of adults with adult-onset dermatomyositis have a myositis-specific antibody (MSA).[5]

Sixty percent of children with juvenile dermatomyositis have a myositis-specific antibody (MSA).[6]

Although no cure for the condition is known, treatments generally improve symptoms.[1]Treatments may include medication,physical therapy,exercise, heat therapy,orthotics,and assistive devices, and rest.[1]Medications in thecorticosteroidsfamily are typically used with other agents such asmethotrexateorazathioprinerecommended if steroids are not working well.[1]Intravenous immunoglobulinmay also improve outcomes.[1]Most people improve with treatment and in some, the condition resolves completely.[1]

About one per 100,000 people per year are newly affected.[3]The condition usually occurs in those in their 40s and 50s with women being affected more often than men.[3]People of any age, however, may be affected.[3]The condition was first described in the 1800s.[7]

Signs and symptoms

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The main symptoms include several kinds of skinrashalong withmuscle weaknessin both upper arms or thighs.[2]

Skin

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One form the rashes take is called "heliotrope"(a purplish color) or lilac, but may also bered.It can occur around the eyes along with swelling, but also occurs on the upper chest or back what is called the "shawl" (around the neck) or "V-sign" above the breasts and may also occur on the face, upper arms, thighs, or hands.[8]Another form the rash takes is calledGottron's sign,which is red or violet, sometimes scaly, slightly raisedpapulesthat erupt on any of the finger joints (themetacarpophalangeal jointsor theinterphalangeal joints).[8][9]Gottron's papulesmay also be found over other bony prominences including the elbows, knees, or feet. All these rashes aremade worse by exposure to sunlight,and are often very itchy, painful, and may bleed.[9]

If a person exhibits only skin findings characteristic of DM, without weakness or abnormal muscle enzymes, then he or she may be experiencing amyopathic dermatomyositis (ADM), formerly known as "dermatomyositis sine myositis".[10]

Muscles

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People with DM experience progressively worsening muscle weakness in theproximalmuscles (for example, the shoulders and thighs).[11]Tasks that use these muscles: standing from sitting, lifting, and climbing stairs, can become increasingly difficult for people with dermatomyositis.[11]

Other

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Around 30% of people have swollen, painful joints, but this is generally mild.[12]

In some people, the condition affects the lungs, and they may have a cough or difficulty breathing. If the disease affects the heart,arrhythmiasmay occur. If it affects the blood vessels in the stomach or intestines, which is more common in juvenile DM, the people mightvomit blood,haveblack tarry bowel movements,or may develop ahole somewhere in their GI tract.[12]

There are further complications possible with dermatomyositis. These complications include difficulty swallowing due to the muscles in the esophagus being affected which can result in malnutrition and can cause the breathing of food or liquids, into the lungs.

  • Examples of dermatomyositis
  • Gottron's papules on finger joints
    Gottron's papules on finger joints
  • Gottron's papules on the elbows of a person with juvenile DM
    Gottron's papules on the elbows of a person with juvenile DM
  • Gottron's papules
    Gottron's papules
  • Gottron's bumps on a person with juvenile DM
    Gottron's bumps on a person with juvenile DM
  • Gottron's papules in a severe case of juvenile dermatomyositis
    Gottron's papules in a severe case of juvenile dermatomyositis
  • Heliotrope with swelling around the eyes
    Heliotrope with swelling around the eyes
  • Heliotrope
    Heliotrope
  • Facial rash
    Facial rash
  • Severe rash on the hands, extending up the forearm
    Severe rash on the hands, extending up the forearm
  • Forearm rash
    Forearm rash

Causes

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See also:List of human leukocyte antigen alleles associated with cutaneous conditions

The cause is unknown, but it may result from an initial viral infection or cancer, either of which could raise anautoimmuneresponse.[12]

Between 7 and 30% of dermatomyositis casesarise from cancer,probably as anautoimmuneresponse.[13]The most commonly associated cancers areovarian cancer,breast cancer,andlung cancer.[13]Between 18 and 25 per cent of people with amyopathic DM also have cancer.[9]Malignancy in association with dermatomyositis is more prevalent after age 60.

Some cases are inherited, and HLA subtypesHLA-DR3,HLA-DR52,andHLA-DR6seem to create a disposition to autoimmune dermatomyositis.[12]

Diagnosis

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Calcification from dermatomyositis
X-Ray of the knee in a person with dermatomyositis.
Micrographof dermatomyositis,muscle biopsy,H&E stain

The diagnosis of dermatomyositis is based on five criteria, which are also used to differentially diagnose with respect topolymyositis:[10]

  1. Muscle weakness in both thighs or both upper arms
  2. Using ablood test,finding higher levels ofenzymesfound inskeletal muscle,includingcreatine kinase,aldolase,andglutamate oxaloacetate,pyruvate transaminasesandlactate dehydrogenase
  3. Usingelectromyography(testing of electric signalling in muscles), finding all three of: erratic, repetitive, high-frequency signals; short, low-energy signals between skeletal muscles andmotor neuronsthat have multiplephases;and sharp activity when a needle is inserted into the muscle
  4. Examining amuscle biopsyunder a microscope and findingmononuclear white blood cellsbetween the muscle cells, and finding abnormal muscle cell degeneration and regeneration, dying muscle cells, and muscle cells being consumed by other cells (phagocytosis)
  5. Rashestypical of dermatomyositis, which include heliotrope rash, Gottron sign, and Gottron papules

The fifth criterion is what differentiates dermatomyositis from polymyositis; the diagnosis is considered definite for dermatomyositis if three of items 1 through 4 are present in addition to 5, probable with any two in addition to 5, and possible if just one is present in addition to 5.[10]

Dermatomyositis is associated withautoantibodies,especiallyantinuclear antibodies(ANA).[12]Around 80% of people with DM test positive for ANA and around 30% of people have myositis-specific autoantibodies which include antibodies toaminoacyl-tRNA synthetases(anti-synthetase antibodies), including antibodies againsthistidine—tRNA ligase(Anti-Jo1); antibodies tosignal recognition particle(SRP); andanti-Mi-2 antibodies.[12]

Magnetic resonance imagingmay be useful to guide muscle biopsy and to investigate involvement of internal organs;[14]X-raymay be used to investigate joint involvement andcalcifications.[15]

A given case of dermatomyositis may be classified as amyopathic dermatomyositis if only skin is affected and no muscle weakness for longer than 6 months is seen according to one 2016 review,[10]or two years according to another.[9]

Classification

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Dermatomyositis is a form of systemicconnective tissue disorder,a class of diseases that often involves autoimmune dysfunction.[12][16]

It has also been classified as an idiopathicinflammatory myopathy,along with polymyositis, necrotizing autoimmune myositis, cancer-associatedmyositis,and sporadicinclusion body myositis.[17]

A form of this disorder that occurs prior to adulthood is known asjuvenile dermatomyositis.[18]

Treatment

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No cure for dermatomyositis is known, but the symptoms can be treated. Options include medication, physical therapy, exercise, heat therapy (including microwave and ultrasound), orthotics and assistive devices, and rest. The standard treatment for dermatomyositis is acorticosteroiddrug, given either in pill form or intravenously. Immunosuppressant drugs, such asazathioprineandmethotrexate,may reduce inflammation in people who do not respond well toprednisone.Periodic treatment usingintravenous immunoglobulincan also improve recovery. Other immunosuppressive agents used to treat the inflammation associated with dermatomyositis includecyclosporine A,cyclophosphamide,andtacrolimus.[19]

Physical therapy is usually recommended to prevent muscle atrophy and to regain muscle strength and range of motion. Many individuals with dermatomyositis may need a topical ointment, such as topical corticosteroids, for their skin disorder. They should wear high-protection sunscreen and protective clothing. Surgery may be required to remove calcium deposits that cause nerve pain and recurrent infections.[20]

Antimalarialmedications, especiallyhydroxychloroquineandchloroquine,are used to treat the rashes, as is done for similar conditions.[9]

Rituximabis used when people do not respond to other treatments.[21][22]

As of 2016, treatments for amyopathic dermatomyositis in adults did not have a strong evidence base; published treatments included antimalarial medications,steroids,taken or orally orapplied to the skin,calcineurin inhibitorsapplied to the skin,dapsone,intravenous immunoglobulin,methotrexate,azathioprine,andmycophenolate mofetil.None appears to be very effective; among them, intravenous immunoglobulin has had the best outcomes.[10]

Prognosis

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Before the advent of modern treatments such as prednisone, intravenous immunoglobulin,plasmapheresis,chemotherapies,and other drugs, the prognosis was poor.[23]

The cutaneous manifestations of dermatomyositis may or may not improve with therapy in parallel with the improvement of the myositis. In some people, the weakness and rash resolve together. In others, the two are not linked, with one or the other being more challenging to control. Often, cutaneous disease persists after adequate control of the muscle disease.[24][25]

The risk of death from the condition is much higher if the heart or lungs are affected.[17][20]

Epidemiology

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Incidence of DM peaks at ages 40–50, but the disease can affect people of all ages.[26][3]It tends to affect more women than men.[3]The prevalence of DM ranges from one to 22 per 100,000 people.[27][28][29]

History

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The diagnostic criteria were proposed in 1975 and became widely adopted.[9][30]Amyopathic DM, also called DM sine myositis, was named in 2002.[9]

People who were affected with dermatomyositis

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Research

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As of 2016, research was ongoing into causes for DM, as well asbiomarkers;[36]clinical trials were ongoing for use of the following drugs in DM:ajulemic acid(Phase II),adrenocorticotropic hormonegel (Phase IV, open label), IMO-8400, an antagonist of Toll-like receptor 7,8 and 9 (Ph II),abatacept(Phase IV, open label), andsodium thiosulfate(Phase II).[9]

References

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  1. ^abcdefghijklmnopqrs"Dermatomyositis".GARD.2017.Archivedfrom the original on 5 July 2017.Retrieved13 July2017.
  2. ^abCallen JP, Wortmann RL (September 2006). "Dermatomyositis".Clinics in Dermatology.24(5): 363–373.doi:10.1016/j.clindermatol.2006.07.001.PMID16966018.
  3. ^abcdefghij"Dermatomyositis".NORD (National Organization for Rare Disorders).2015.Archivedfrom the original on 19 February 2017.Retrieved13 July2017.
  4. ^Tudorancea AD, Ciurea PL, Vreju AF, Turcu-Stiolica A, Gofita CE, Criveanu C, Musetescu AE, Dinescu SC (July 2021)."A Study on Dermatomyositis and the Relation to Malignancy".Current Health Sciences Journal.47(3): 377–382.doi:10.12865/CHSJ.47.03.07.PMC8679146.PMID35003769.
  5. ^Tansley SL, McHugh NJ, Wedderburn LR (2013)."Adult and juvenile dermatomyositis: are the distinct clinical features explained by our current understanding of serological subgroups and pathogenic mechanisms?".Arthritis Research & Therapy.15(2): 211.doi:10.1186/ar4198.PMC3672700.PMID23566358.Myositis-specific autoantibodies (MSAs) can now be identified in 80% of adults.
  6. ^Papadopoulou C, Chew C, Wilkinson MG, McCann L, Wedderburn LR (June 2023)."Juvenile idiopathic inflammatory myositis: an update on pathophysiology and clinical care".Nature Reviews Rheumatology.19(6): 343–362.doi:10.1038/s41584-023-00967-9.PMC10184643.PMID37188756.Approximately 60% of patients with JDM are positive for a myositis-specific antibody (MSA).
  7. ^"History of Dermatomyositis".Dermatomyositis.2009. pp. 5–8.doi:10.1007/978-3-540-79313-7_2.ISBN978-3-540-79312-0.
  8. ^abCallen JP (June 2010). "Cutaneous Manifestations of Dermatomyositis and Their Management".Current Rheumatology Reports.12(3): 192–197.doi:10.1007/s11926-010-0100-7.PMID20425525.S2CID29083422.
  9. ^abcdefghKuhn A, Landmann A, Bonsmann G (October 2016). "The skin in autoimmune diseases-Unmet needs".Autoimmunity Reviews.15(10): 948–54.doi:10.1016/j.autrev.2016.07.013.PMID27481041.
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  13. ^abDi Rollo D, Abeni D, Tracanna M, Capo A, Amerio P (October 2014)."Cancer risk in dermatomyositis: a systematic review of the literature".Giornale Italiano di Dermatologia e Venereologia.149(5): 525–537.PMID24975953.
  14. ^Simon JP, Marie I, Jouen F, Boyer O, Martinet J (14 June 2016)."Autoimmune Myopathies: Where Do We Stand?".Frontiers in Immunology.7:234.doi:10.3389/fimmu.2016.00234.PMC4905946.PMID27379096.
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  16. ^"ICD-10 Systemic connective tissue disorders (M30-M36)".WHO.Archivedfrom the original on 8 February 2017.Retrieved9 December2016.
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  18. ^Feldman BM, Rider LG, Reed AM, Pachman LM (June 2008). "Juvenile dermatomyositis and other idiopathic inflammatory myopathies of childhood".Lancet.371(9631): 2201–2212.doi:10.1016/S0140-6736(08)60955-1.PMID18586175.S2CID205951454.
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  22. ^Wright NA, Vleugels RA, Callen JP (January 2016). "Cutaneous dermatomyositis in the era of biologicals".Seminars in Immunopathology.38(1): 113–21.doi:10.1007/s00281-015-0543-z.PMID26563285.S2CID7104535.
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  28. ^Bernatsky S, Joseph L, Pineau CA, Belisle P, Boivin JF, Banerjee D, Clarke AE (July 2009). "Estimating the prevalence of polymyositis and dermatomyositis from administrative data: age, sex and regional differences".Annals of the Rheumatic Diseases.68(7): 1192–1196.doi:10.1136/ard.2008.093161.PMID18713785.S2CID21500536.
  29. ^Bendewald MJ, Wetter DA, Li X, Davis MD (2010)."Incidence of Dermatomyositis and Clinically Amyopathic Dermatomyositis: A Population-Based Study in Olmsted County, Minnesota".Archives of Dermatology.146(1): 26–30.doi:10.1001/archdermatol.2009.328.PMC2886726.PMID20083689.
  30. ^Bohan A, Peter JB (13 February 1975). "Polymyositis and Dermatomyositis: (First of Two Parts)".New England Journal of Medicine.292(7): 344–347.doi:10.1056/nejm197502132920706.PMID1090839.andBohan A, Peter JB (20 February 1975). "Polymyositis and Dermatomyositis: (Second of Two Parts)".New England Journal of Medicine.292(8): 403–407.doi:10.1056/nejm197502202920807.PMID1089199.
  31. ^"Greek Reporter: 'Maria Callas did not kill herself from grief for Onassis, a rare disease cost her career and life'".GR Reporter. 28 December 2010.Archivedfrom the original on 4 January 2015.Retrieved1 January2015.
  32. ^"Laurence Olivier Dies: 'The Rest Is Silence'".People Magazine. 24 July 1989.Archivedfrom the original on 10 March 2011.Retrieved16 July2012.
  33. ^"Forgotten: Ricky Bell".Pro Football Weekly. 8 January 2010. Archived fromthe originalon 11 January 2010.Retrieved26 January2010.
  34. ^Jones T (12 October 2011)."Rob Buckman obituary".The Guardian.Archivedfrom the original on 1 October 2013.Retrieved16 July2012.
  35. ^"'Dangal' actor Suhani Bhatnagar succumbs to dermatomyositis: Know about this rare condition ".The Times of India.18 February 2024.
  36. ^Ramos-E-Silva M, Pinto AP, Pirmez R, Cuzzi T, Carneiro SC (1 August 2016). "Dermatomyositis—Part 1: Definition, Epidemiology, Etiology and Pathogenesis, and Clinics".Skinmed.14(4): 273–279.PMID27784516.

Public DomainThis article incorporatespublic domain materialfromNINDS Dermatomyositis Information Page.United States Department of Health and Human Services.Retrieved12 December2016.

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