A Very Weak Young Girl with a Rash

The first patient of the morning is being examined by your resident who thinks this may be a case of a "fascinoma."

A 7-year-old girl has muscle weakness, is easily fatigued, has occasional fevers, some recent difficulty swallowing. She also has a rash on her face.

Physical examination: Erythema and puffiness of the eyelids and violaceous, flat-topped papules on dorsal interphalangeal joints…also erythema of the cuticles.

Significant laboratory findings: Sed rate = 95; marked elevation of SGOT, SGPT, LDH; CPK = 15,000; +rheumatoid factor (RF).

Note the reddish blue rash on her face.

A closer look at the reddish blue rash on her face.

There are reddish-blue lichenified papules on her knees.

Note the reddish-blue lichenified papules on her knuckles, too. Some seem to have ulcerated. Note, too, how erythematous her cuticles are.

The most likely diagnosis is: A. Rheumatoid arthritis B. Discoid lupus C. A vitamin deficiency D. Dermatomyositis None of the above

Answer: D. Dermatomyositis. Idiopathic inflammatory disorder of the skin and striated muscle. More common in adult women but incidence equal in childhood; bimobdal incidence; in adults, 20% chance of malignancy.

Dermatomyositis clinical presentation: Insidious onset of weakness, fatigue, and rash is most common; muscle tenderness, and rash. Sequelae include calcinosis, then ulcers; later sinus formation and pain.

Dermatomyositis clinical presentation: Proximal muscles most commonly affected: Shoulder, hip, neck flexors, oropharyngeal muscles. Other manifestations: arthralgias/arthritis 20%; lung disease; ECG abnormalities, vasculitis.

Dermatomyositis cutaneous manifesations: heliotrope rash (Gottron’s papules); periungual/cuticular telangiectasia; shawl sign

Dermatomyositis diagnosis: Combination of clinical and laboratory: Electromyography; 10% have +RF; false +ANA in 33.3%; anti-Jo-1 antibody is the most specific auto antibody .

MRI of affected areas may show disease even when muscle enzymes are normal; EMG: polyphasic motor unit action potentials with short duration and low amplitude.

For diagnosis of dermatomyositis, 4 of 5 Bohan and Peter criteria required.

Dermatomyositis treatment: for muscle component, corticosteroids, typically with an immunosuppressive agent. For cutaneous disease, sun avoidance, topical corticosteroids, antimalarials, immune globulins, methotrexate.

Patients with dermatomyositis may present without muscle weakness and only cutaneous signs, ie, classic periorbital “heliotrope” rash.

Gottron's papules.

Amyopathic dermatomyositis: Characterized by presence of dermatomyositis for ≥6 months in persons who have normal muscle enzymes, no clinically significant muscle weakness. Muscle involvement may not become apparent for several years. Skin signs should be considered pathognomonic for disease and requires close follow-up.n