Dermatomyositis

Dermatomyositis
Discrete red areas overlying the knuckles in 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 a long-term inflammatory disorder which affects the skin and the muscles.[1] Its symptoms are generally a skin rash and 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 include calcium deposits in muscles or skin.[1]

The cause is unknown.[1] Theories include that it is an autoimmune disease or a result of a viral infection.[1] Dermatomyositis may develop as a paraneoplastic syndrome associated with several forms of malignancy.[4] It is a type of inflammatory myopathy.[1] Diagnosis is typically based on some combination of symptoms, blood tests, electromyography, and muscle 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 the corticosteroids family are typically used with other agents such as methotrexate or azathioprine recommended if steroids are not working well.[1] Intravenous immunoglobulin may 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]

  1. ^ a b c d e f g h i j k l m n o p q r s "Dermatomyositis". GARD. 2017. Archived from the original on 5 July 2017. Retrieved 13 July 2017.
  2. ^ Cite error: The named reference Cal2006 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h "Dermatomyositis". NORD (National Organization for Rare Disorders). 2015. Archived from the original on 19 February 2017. Retrieved 13 July 2017.
  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. PMC 8679146. PMID 35003769.
  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. PMC 3672700. PMID 23566358. 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. PMC 10184643. PMID 37188756. 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. ISBN 978-3-540-79312-0.