Juvenile dermatomyositis in Child
Alerts and Notices
Synopsis
Childhood type dermatomyositis, also known as juvenile dermatomyositis (JDM), is an idiopathic multisystem inflammatory disorder where muscle inflammation is accompanied by a skin rash. It is typically first detected in children aged between 2 and 15 years.
Cutaneous lesions may precede muscle disease by anywhere from weeks to more than 4 years and may be extremely pruritic. Exposure to sunlight may exacerbate the cutaneous lesions. Other characteristic features may include flat erythema of the upper back and posterior neck and shoulders (shawl sign) as well as a similarly presenting macular erythema of the anterior neck and upper chest (V sign) that can worsen with ultraviolet (UV) exposure. Patients may also have poikiloderma over the lateral hip (holster sign). Myositis (inflammation of muscle) usually develops insidiously, but sometimes abruptly, or may not occur at all (amyopathic or hypomyopathic dermatomyositis).
Muscle findings include symmetric proximal muscle weakness, usually of the shoulder and pelvic girdles.
In acute phases, pain and tenderness may occur and palpation may have a doughy feel. In addition, the patient's gait may be abnormal. Patients may complain of difficulty climbing stairs and brushing their hair. Upper palatal muscle and esophageal dysfunction may be noted, resulting in dysphonia, dysphagia, anorexia, and weight loss. Neck flexors are usually weak, and the patient may be unable to raise his or her head at all. Fever and fatigue are other common symptoms, and patients may also report arthralgia.
While children experience calcinosis cutis, muscle necrosis, and gingival and periungual telangiectasias more frequently than adults, JDM is a milder disease overall than adult dermatomyositis. There is a lower frequency of interstitial lung disease and lower overall mortality. Moreover, the association of malignancy with dermatomyositis is extremely uncommon in JDM.
Signs of severity in childhood include systemic vasculopathy, resulting in ulcerative disease of the skin and other organs (especially in the lungs or gastrointestinal tract), high severity of muscle disease, and endomysial fibrosis on muscle biopsy. The presence of these signs may indicate disease that is refractory to first-line treatment.
Dermatomyositis may be induced by medications, usually seen in adults, including hydroxyurea, penicillamine, interferon beta, statins, and ipilimumab. Acute onset / flares of dermatomyositis have been reported in association with ingestion of IsaLean, an herbal supplement.
Acquired lipodystrophy and acanthosis nigricans occurring in the setting of insulin resistance has infrequently been reported with JDM.
Codes
ICD10CM:M33.00 – Juvenile dermatomyositis, organ involvement unspecified
SNOMEDCT:
1212005 – Juvenile dermatomyositis
Look For
Subscription Required
Diagnostic Pearls
Subscription Required
Differential Diagnosis & Pitfalls
The most underdiagnosed form of the disease is the eruption without muscle weakness.- For patients with myositis, one must rule out other systemic causes of myopathy (eg, thyroid disorders, electrolyte disturbances, vitamin D deficiency, mitochondrial / metabolic myopathies, or infection) and distinguish JDM from other connective tissue diseases such as polymyositis, mixed connective tissue disease, and systemic lupus erythematosus (SLE). In JDM, fingers may appear more sausage-like than with SLE.
- Juvenile polymyositis is a rare form of idiopathic inflammatory myopathy seen in the pediatric population.
- Acute lesions of erythropoietic protoporphyria may have similar locations, especially on the dorsum of the hands, but usually there is no muscle weakness.
- Scalp involvement may be present in the majority of patients but is frequently misdiagnosed as psoriasis or seborrheic dermatitis.
- Atopic dermatitis
- Lichen planus
- Polymorphous light eruption
- Phototoxic / photoallergic drug eruptions
- Acute graft-versus-host disease
- HIV infection
- Sarcoidosis
- Amyloidosis
- Acral erythema
Best Tests
Subscription Required
Management Pearls
Subscription Required
Therapy
Subscription Required
References
Subscription Required
Last Reviewed:06/25/2020
Last Updated:06/25/2020
Last Updated:06/25/2020
Patient Information for Juvenile dermatomyositis in Child
Overview
Juvenile dermatomyositis is a condition of muscle inflammation and weakness, with skin rash or other skin changes, including eye and fingernail changes. The disease first appears when the patient is a child.The cause is uncertain, but it appears to be related to dysfunction of the immune system. Juvenile dermatomyositis tends to be milder than adult-onset dermatomyositis.
Who’s At Risk
Most cases of juvenile dermatomyositis are found in patients 10-15 years old, but it may be detected earlier.It is suggested that certain conditions trigger the illness. These may include a family or genetic connection, a viral infection, or certain medications.
Signs & Symptoms
The most common symptoms are rash and muscle weakness, usually in the shoulders, hips, back, and neck. The rash is a red, very itchy skin eruption in sun-exposed areas, particularly the face and backs of hands. The rash and muscle weakness may not start at the same time .Other symptoms include muscle tenderness, aching, pain, falling, trouble swallowing, and a hoarse or weak voice. You may have difficulty getting up from sitting position, climbing stairs, combing your hair, or reaching for high items on a shelf. You may feel tired, irritable, and generally not well.
Some children develop hard lumps of calcium (calcinosis) in the skin that impede joint and muscle movement.
Dermatomyositis can also present in or around the eyes and fingernails. Your scalp may have red, itchy, scaly plaque.
Self-Care Guidelines
Your skin will be sensitive to sunlight. Stay out of the sun, use sunblock (SPF 45+), and wear sun-protective clothing, such as long sleeves, long pants, and a wide-brimmed hat. Connect with patient or parent support groups, such as Myositis Support Group.When to Seek Medical Care
If your child has muscle weakness and rash, contact your pediatrician. Seek immediate medical care for complications, such as difficulty breathing, difficulty swallowing, and skin ulcers.Treatments
Treatment can improve your skin and muscle involvement. Your doctor may prescribe corticosteroids to control your symptoms, antimalarial medication for your rash, and topical skin treatments. You may also benefit from physical therapy to strengthen your muscles.For severe complications, your doctor or pediatrician may refer your child to a specialized myositis center, where they have the expertise to handle urgent complications.
Juvenile dermatomyositis in Child