Amyopathic dermatomyositis

Other Names: ADM; Dermatomyositis sine myositis Amyopathic dermatomyositis is a form of dermatomyositis characterized by the presence of typical skin findings without muscle weakness.

Cause

It is thought to be caused by deposition of complement in the blood vessels. Most patients experience symmetric proximal muscle weakness.

Signs and symptoms

Some of the skin changes that suggest dermatomyositis include a pink rash on the face, neck, forearms and upper chest; Gottron's papules and heliotrope eyelids. Pruritis and photosensitivity are common, as is scalp inflammation and thinning of the hair. While patients with amyopathic dermatomyositis should not have clinically evident muscle weakness, minor muscle abnormalities may be included. Fatigue is reported in at least 50% of patients. Some cases have been associated with internal malignancy and/or interstitial lung disease.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Abnormal eyelid morphology(Abnormality of the eyelid)
• Autoimmunity(Autoimmune disease)
• EMG abnormality
• Erythema
• Inflammatory myopathy
• Myalgia(Muscle ache)
• Periorbital edema
• Proximal muscle weakness(Weakness in muscles of upper arms and upper legs)

30%-79% of people have these symptoms

• Abnormal hair quantity
• Abnormality of the nail
• Acrocyanosis(Persistent blue color of hands, feet, or parts of face)
• Arthralgia(Joint pain)
• Arthritis(Joint inflammation)
• Chondrocalcinosis(Calcium deposits in joints)
• Diffuse reticular or finely nodular infiltrations
• Dry skin
• Fatigue(Tired)
• Muscular hypotonia(Low or weak muscle tone)
• Papule
• Pruritus(Itching)
• Pulmonary fibrosis
• Recurrent respiratory infections(Frequent respiratory infections)
• Respiratory insufficiency(Respiratory impairment)
• Skin ulcer(Open skin sore)
• Weight loss

5%-29% of people have these symptoms

• Abnormal eosinophil morphology
• Aplasia/Hypoplasia of the skin(Absent/small skin)
• Breast carcinoma(Breast cancer)
• Cellulitis(Bacterial infection of skin)
• Cutaneous photosensitivity(Photosensitive skin)
• Dysphonia(Inability to produce voice sounds)
• Feeding difficulties in infancy
• Fever
• Gangrene(Death of body tissue due to lack of blood flow or infection)
• Gastrointestinal stroma tumor
• Lung adenocarcinoma
• Lymphoma(Cancer of lymphatic system)
• Myocardial infarction(Heart attack)
• Myocarditis(Inflammation of heart muscle)
• Pericarditis(Swelling or irritation of membrane around heart)
• Pulmonary arterial hypertension
• Increased blood pressure in blood vessels of lungs
• Sinus tachycardia
• Telangiectasia of the skin
• Vasculitis(Inflammation of blood vessel)

Diagnosis

The diagnosis is made by typical skin findings and evidence of muscle injury. Notably, this patient had a variant of dermatomyositis called amyopathic dermatomyositis, which manifests without muscle involvement.

Treatment

Treatment may include sun avoidance, ample use of sunscreen, topical corticosteroids, antimalarial agents, methotrexate, mycophenolate mofetil, or intravenous (IV) immunoglobulin.

NIH genetic and rare disease info

• NIH info on Amyopathic dermatomyositis

Amyopathic dermatomyositis is a rare disease.