MedGen

A rare pediatric inflammatory rheumatic disease characterized by the presence of arthritis accompanied by either psoriasis or at least two of the following supporting features; presence of nail pitting, onycholysis, dactylitis, or a family history of psoriasis in a first degree relative. Patients are younger than 16 years of age and the disease lasts longer than 6 weeks. [from ORDO]

A rare idiopathic inflammatory myopathy (IIM) historically characterized by symmetric proximal muscle weakness, elevated muscle enzymes (creatine kinase), myopathic findings on electromyography, and muscle biopsy showing endomyial infiltration composed mainly of macrophages and lymphocytes. The features are non-specific, thus the disease should be distinguished from similar entities with specific clinical, immunological, histological features, notably dermatomyositis, immune-mediated necrotizing myopathy, anti-synthetase syndrome, inclusion body myositis, and myositis associated with other connective tissue disorder. [from ORDO]

A rare idiopathic inflammatory myopathy (IIM) characterized by evocative skin lesions, muscle involvement with symmetrical proximal muscle weakness, and specific histological features. The clinical subtypes are defined by the presence of myositis-specific antibodies (anti-Mi2, anti-NXP2, anti-TIF1-γ, anti-MDA5, or anti-SAE antibodies) and are associated with specific clinical phenotypes and prognosis. [from ORDO]

Idiopathic inflammatory myopathy is a group of disorders characterized by inflammation of the muscles used for movement (skeletal muscles). Idiopathic inflammatory myopathy usually appears in adults between ages 40 and 60 or in children between ages 5 and 15, though it can occur at any age.

The primary symptom of idiopathic inflammatory myopathy is muscle weakness, which develops gradually over a period of weeks to months or even years. Other symptoms include joint pain and general tiredness (fatigue).

In sporadic inclusion body myositis, the muscles most affected are those of the wrists and fingers and the front of the thigh. Affected individuals may frequently stumble while walking and find it difficult to grasp items. As in dermatomyositis and polymyositis, swallowing can be difficult.

There are several forms of idiopathic inflammatory myopathy, including polymyositis, dermatomyositis, and sporadic inclusion body myositis.

Polymyositis and dermatomyositis involve weakness of the muscles closest to the center of the body (proximal muscles), such as the muscles of the hips and thighs, upper arms, and neck. People with these forms of idiopathic inflammatory myopathy may find it difficult to climb stairs, get up from a seated position, or lift items above their head. In some cases, muscle weakness may make swallowing or breathing difficult.

Polymyositis and dermatomyositis have similar symptoms, but dermatomyositis is distinguished by a reddish or purplish rash on the eyelids, elbows, knees, or knuckles. Sometimes, abnormal calcium deposits form hard, painful bumps under the skin (calcinosis). [from MedlinePlus Genetics]