DERMATOMYOSITIS
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Dr. Lehman is the
author of many textbook chapters and articles on the care of children and young
adults with dermatomyositis and related conditions. He practices in
If you
want a more detailed discussion of childhood dermatomyositis
click here for information regarding a book I have written.
What is
dermatomyositis?
Dermatomyositis is an acute inflammatory condition
of skin and muscle. There are several distinct types of dermatomyositis which
may ultimately prove to be different diseases. Most often dermatomyositis
presents with increasing fatigue and loss of proximal (thighs and shoulders)
muscle strength accompanied by a heliotrope rash. The characteristic clinical
history is simply of a child who is not able to 'keep up', or who is asking to
be carried more and more often. Difficulty going up and down stairs is often
the manifestation which prompts the family to seek medical attention. These findings
may occur with other illnesses, but a careful pediatric rheumatologist can
often make the diagnosis on the initial examination. This is because many
children have vasculitic lesions of the nail beds ('nailfold
capillary dilatation) and lesions of the skin overlying the proximal interphalangeal joints (Gottren's
papules). These findings almost invariably signal dermatomyositis or a similar
rheumatic disease (scleroderma or progressive systemic sclerosis). Less
frequently the onset of dermatomyositis can be rapid with fever, widespread
vasculitic rash and profound weakness. Both rapid and gradual onset of disease are often accompanied by a sense of being
unwell (malaise) and may be complicated by fever and severe muscle wasting.
Laboratory evaluation typically shows elevation of the CPK, SGOT, and aldolase,
although in some cases only the CPK or aldolase may be abnormal.
Although not pathologically distinguishable, three
distinct patterns of childhood dermatomyositis are clinically recognized. The
most common group consists of children with proximal muscle weakness, mild
heliotrope rash and no findings suggestive of vasculitis. These children often
have a benign illness which resolves over a four to six month period with
corticosteroid therapy. In contrast, children with a marked vasculitic rash, or
typical findings of vascular involvement in the nail beds (nail-fold capillary
abnormalities), or inflammatory papules overlying the interphalangeal
joints (Gottren's papules) most often have a more
chronic relapsing course. Their disease typically improves with corticosteriod or immunosuppressive therapy, but recurs.
Less frequently seen are children with severe rash, markedly elevated muscle
enzyme levels, but only moderate weakness. This special subgroup of children is
often refractory to therapy and may be an entirely different disease.
Another unusual group of children who may be
mistakenly diagnosed as dermatomyositis consists of children who are
incidentally found to have markedly elevated CPK levels (e.g. 20,000 units) when being screened for another reason. These children are
not weak, do not have a heliotropic rash, and remain
well without therapy. Although the precise explanation for this group is
unknown, they most likely have a simple biochemical defect. Muscular dystrophy
also may present with very high CPK levels, but these children are weak.
What do I have to watch out for?
Vasculitic complications of dermatomyositis can
occur in a variety of organs. Mental changes, skin rashes, abdominal pain, and
chest infections are all well recognized complications of dermatomyositis which
may be associated with severe problems. Arthritis may also complicate
dermatomyositis but usually responds to the initiation of corticosteroid
therapy.
How is it treated?
Prednisone in dosages of 0.5 to
2.0 mg/kg/day (depending on the severity of the presentation) are the treatment of choice for mild to moderate dermatomyositis. Special
care must be taken to evaluate the swallowing function and gag reflex of
children at the time of presentation or disease flare since aspiration is a
prominent hazard for those with severe involvement. Chronic abdominal pain is a
common nonspecific finding which may also necessitate a higher corticosteroid
dosage. Although it may be benign, in some children it results from small
vessel vasculitis of the bowel. This can be associated with multiple small
areas of thrombosis and infarction which may perforate with catastrophic
consequences. A less frequent indication for high dose prednisone is the
presence of cerebritis which may be associated with
hallucinations and dementia. Retinal vasculitis may also be present.
In most situations the corticosteroid dosage can be
monitored by following serial CPK or aldolase levels. The treating physician must
be aware that prednisone themselves may cause muscle weakness (steroid myopathy). If the patient is becoming weaker without a
corresponding increase in the muscle enzyme levels, it may be necessary to
rapidly taper the corticosteroid dosage. However, this may be associated with a
disease flare. 'IV bolus' prednisone are useful if a rapid response is need for
critically ill children with dermatomyositis, but are associated with
potentially severe side effects.
For some children the heliotrope rash remains a
significant problem despite clinical improvement in muscle strength with
corticosteroid therapy. Hydroxychloroquine may be beneficial for these children
in preference to raising the corticosteroid dosage. If corticosteroid
containing topical preparations are recommended, careful consideration
must be given to potential long-term side-effects including subcutaneous
atrophy.
Most children will recover completely with
prednisone alone. However, some will have persistent, active disease or develop
unacceptable corticosteroid side effects. Methotrexate is often beneficial for
these children. Low dose oral methotrexate at 10 mg/M2, which
has been very useful for JRA, has been relatively ineffective for childhood
dermatomyositis. Larger doses of methotrexate (0.1 mg/kg gradually
increased to 1 mg/kg) administered weekly, intramuscularly or intravenously,
have been associated with a dramatic improvement. Hepatic toxicity and white
blood cell levels must be monitored carefully. Intravenous methotrexate therapy
in this dose range may also be associated with significant nausea, which may be
reduced by premedication. For most children the
maximum necessary dosage of methotrexate is 1 mg/kg (with a maximum of 50 mg).
However, higher doses have been used successfully in selected cases.
Intravenous cyclophosphamide therapy has also been
used successful in many centers for children with severe dermatomyositis. A
variety of regimens have been utilized ranging from 10 mg/kg weekly to 1 gm/M2
monthly. As with methotrexate, cyclophosphamide administration requires careful
monitoring of hematological parameters. Cyclophosphamide has the advantage of
not being associated with hepatic cirrhosis, but methotrexate is less strongly
associated with a subsequent risk of sterility or neoplastic
disease. In addition, methotrexate can be administered on an outpatient basis
without concern about possible bladder toxicity.
New studies suggest the etanercept or other agents
which block tumor necrosis factor (TNFa) may be less
toxic and more effective in treating children with dermatomyositis. Dr. Lehman is now using this therapy at the
Hospital for Special Surgery. “We have
had some children dramatically improve, but others do not” says Dr.
Lehman. The right answer and how
children with dermatomyositis may differ in their
response to drugs isn’t yet clear.
Limited experience is available with the use of
intravenous gammaglobulin therapy. In small studies
it has been associated with a significant steroid sparing effect. However,
prolonged therapy was required (nine months) and flares occurred when treatment
was discontinued. The excessive costs of this therapy make these limited
benefits of questionable utility unless the patient has failed to respond to
less costly therapies. There is also an increasing experience with cyclosporine
A. Despite initially promising results many centers report a general lack of
long term efficacy. No controlled studies have been reported.
Diffuse calcification of subcutaneous tissues or
muscle groups is a potential complication of dermatomyositis which may be
severely debilitating. Small areas of discrete calcification do not warrant
surgical intervention unless they are causing discomfort. Larger areas should
be treated conservatively if at all possible. Poor wound healing often results
in an unsatisfactory surgical result. Recurrent episodes of inflammation at
sites of calcification may be continuing sources of discomfort for the patient.
Colchicine (0.6 mg b.i.d.)
may be helpful in reducing the frequency of these episodes. Some experts have had excellent success
using bisphosphonates to reduce the
calcifications. Secondary infection of
calcium deposits which have broken through the skin is a constant concern, and cellulitis may require intravenous antibiotic therapy.
A few patients will develop severe, diffuse
calcification (calcinosis universalis)
following the acute phase of their dermatomyositis. This complication is
associated with severe restriction. No satisfactory regimen for alleviating
this condition has been found. Regimens such as editronate
which interfere with calcification have more profound effects on normal than
ectopic bone resulting in an unacceptable frequency of fractures. Although low
dose warfarin therapy has been recommended, most centers have found it
ineffective and potentially dangerous. The extreme weakness and poor mobility
of these patients are often complicated by depression and malaise with
resultant inanition. Pneumonia secondary to poor chest wall function and
resultant cardiorespiratory function is a frequent
cause of death. These patients require a multidisciplinary team approach and
are best referred to centers with extensive experience in their management.
In addition to medical management, patients with
dermatomyositis or polymyositis require an ongoing program of physical and
occupational therapy to prevent continuing weakness and the development of
contractures. Passive range of motion and icing are of benefit even during
periods of active muscle inflammation, but active range-of-motion and
isometrics should be withheld until the muscle enzyme levels are declining.
What is the long term outlook?
The long term outlook for children with
dermatomyositis is good. Although some children do have very severe disease
most will eventually recover nearly full function.
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Reviewer’s comments on It’s Not Just Growing Pains
“Dr. Tom Lehman’s experience and compassion are evident on every page of this
book, and they help guide the reader—child, parent,
and healthcare professional alike – through the
world of childhood arthritis. This book
is an absolute gem written with a single goal in mind: improve the lives of kids with arthritis.” -- Jack Klippel, M.D. President and
CEO of the Arthritis Foundation
“Dr. Lehman has given parents and families of children with
arthritis the first book that speaks to the parent and child as equals. His book explains the illnesses, the
medications, the lab tests, and the disease course in simple, understandable
lay language and givens them valuable insight into how a pediatric
rheumatologist thinks. Bravo!”-- Charles Spencer, M.D.,
Professor of Clinical Pediatrics,
It’s not just
growing pains.
A guide to childhood muscle, bone, and joint pain,
rheumatic diseases and the latest treatments
Click here to see the table of
contents
It
has always been a frustration trying to answer the many questions I have
received from people over the web. I can’t
take the time and give them the detail I would like to. I have to take care of my patients. This book is a distillation of my experience
answering questions for parents and health professionals over 25 years of
practice. If you want to know about the
diseases, the tests, the medications, or how to be sure you are getting the
best care– If you are the family member of a child with joint pains, this book will give you the answers. There is an entire chapter just on
dermatomyositis. If you are a general
physician, a pediatrician, or a nurse who cares for children with these
diseases it will answer many of the questions families ask you, and you can
recommend it to them. It will also
answer many of your questions about what shots to give, what precautions to
take, and the other questions families, pediatricians, and other health care
providers have asked me over the years.
Dr. Lehman is the author of many
textbook chapters and articles on the care of children and young adults with
rheumatic diseases including SLE, JRA, dermatomyositis, scleroderma,
Click here if you are interested in making an appointment to see
Dr. Lehman
Resources:
If you are interested in books about childhood rheumatic disease click here
In the
Dr. Lehman
is the author of many textbook chapters and articles on the care of children
and young adults with SLE. He practices
in
The Arthritis Foundation also works with
children with dermatomyositis.
Click for BOOKS dealing with
childhood rheumatic diseases
This site provided by Thomas J. A. Lehman MD
Chief, Division of Pediatric Rheumatology
The Hospital for Special
Surgery
535 E 70 St,
212-606-1151, fax 212-606-1938, e-mail goldscout@aol.com