Juvenile dermatomyositis M33.0

Rare form of dermatomyositis in children. In contrast to adult forms there is no association with malignant diseases.

A clinical distinction is made between:

• acutely intermittent form
• chronic progressive form.

Unknown. Vasculitic etiopathogenesis and association with HLA-B8 are discussed. Previous (viral) infections are often suspected as triggers.

In children, usually occurring before the age of 12. Frequency peaks in the 6th LJ and 10 LJ for girls and in the 6th LJ for boys. Girls are affected 2-5 times as often as boys (these figures must be verified).

• Frequent insidious onset with feeling of illness, fatigue, muscle weakness, skin rash, fever. Usually progresses over several months. In some cases, highly acute courses can also occur with initially high fever, strong general feeling of illness and muscle pain.
• Integument: S.u. Dermatomyositis. Initially mostly dry, scaly or inflammatory reddened plaques in the joint areas of the extremities. In 50% of patients calcinosis cutis, muscle contractures or palmoplantar hyperkeratosis are impressive. The occurrence of halo-naevi is rarer.
• Extracutaneous manifestations: Various organ systems are affected, including the gastrointestinal tract with motility disorders, hemorrhages, ulcerations and perforations as an expression of early vasculitis. Joints (arthralgias or arthritides in up to 2/3 of cases), heart and lungs can be affected, either directly (diffuse interstitial fibrosis, pneumonia) or as a result of severe muscle weakness. Mostly increasing muscle weakness in the proximal muscle groups of the upper and lower extremities.

S.u. Dermatomyositis.

CK and aldolase are more frequently elevated than in the adult form.

Non-specific inflammatory parameters such as BSG and CRP are often within the normal range.

ANA. positive in 20-25% of cases

TIF-1 antibody positive at 30%.

NXP-2 antibody at 25%.

S.u. Dermatomyositis. Cooperation with the pediatrician.

• During acute attacks of glucocorticoids such as prednisolone (e.g. Decortin) 1-2 mg/kg bw/day p.o. Slow reduction over weeks to months. In therapy-resistant cases, the use of azathioprine, methotrexate, Ciclosporin A, hydroxychloroquine is described as successful.
• Own successes were achieved with IVIG therapy.
• Aluminium hydroxide can be used to reduce calcinosis cutis. Circumscribed calcifications can be removed surgically.

Inexpensive, with high rate of complete healing.

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