Page 104 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-19 Integumentary System

MANIFESTATIONS OF DERMATOMYOSITIS

Periorbital heliotrope rash
with purple discoloration
and edema

Difficulty in swallowing
DERMATOMYOSITIS due to pharyngeal
muscle weakness may
lead to aspiration
pneumonia.
Dermatomyositis is a chronic connective tissue disease
that can be associated with an underlying internal
malignancy. This connective tissue disease shares Weakness of diaphragm
similarities with polymyositis, but the latter has no and intercostal muscle
cutaneous findings. Up to one third of patients with causes respiratory
dermatomyositis have an underlying malignancy. The insufficiency
myositis is often prominent and manifests as tenderness or failure.
and weakness of the proximal muscle groups. The Weakness of
pelvic and shoulder girdle muscles are the ones most central muscle
commonly affected. Dermatomyositis sine myositis is a groups evidenced
well-recognized variant that has only the cutaneous by difficulty in
findings; evidence of muscle involvement is absent. climbing stairs,
Clinical Findings: Dermatomyositis has a bimodal rising from chairs, Gottron’s papules.
age of onset, with the most common form occurring in and combing hair Erythematous or
the female adult population, usually between the ages violaceous, scaly
of 45 and 60 years, and a smaller peak in childhood papules on
at about 10 to 15 years of age. African Americans are dorsum of
affected three to four times more often than Cauca- interphalangeal
sians. Dermatomyositis has an insidious onset, with the joints
development of proximal muscle weakness in associa-
tion with various dermatological findings. Skin findings
start slowly and are nonspecific at first. Usually, there
is some mild erythema on the hands and sun-exposed
regions of the head and neck. Over time, the more
typical cutaneous findings become evident. Pruritus is
a common complaint, and patients not infrequently
complain of severe scalp pruritus well before any signs
or symptoms of dermatomyositis appear.
The heliotrope rash of dermatomyositis is one of the
most easily recognized and specific findings. It is mani- Difficulty in arising
fested by periorbital edema and a light purple discolor- from a chair is often
ation of the periorbital skin. The skin is tender to the an early complaint.
touch. Hyperemia of the nail beds and dilated capillary
loops are noticeable and are similar to those seen in
progressive systemic sclerosis or lupus erythematous.
The dilated capillary loops are best appreciated with the
use of a handheld dermatoscope that serves to magnify
the region of interest.
Purplish to red, scaly papules develop on the dorsum
of the hands overlying the joints of the phalanges.
These are not Heberden’s nodes, which are a manifesta-
tion of osteoarthritis seen as dermal swellings overlying
the distal interphalangeal joints. The papules seen in
dermatomyositis have been termed Gottron’s papules.
Gottron’s papules may be seen overlying any joint on
the hands, as well as other joints such as the elbows and Longitudinal section of muscle showing intense
knees. The skin findings on the dorsal hands have led inflammatory infiltration plus degeneration
to the term “mechanic’s hands.” This refers to the and disruption of muscle fibers
ragged appearance of the hands in dermatomyositis;
they resemble the hands of a mechanic that have suf-
fered chronic trauma, abrasions, and erosions second-
ary to the occupation.
The “shawl sign” is a cutaneous finding seen on the Patients with dermatomyositis also complain of pho- Leukocytoclastic vasculitis also is seen much more fre-
upper back and chest. The shawl sign is so named tosensitivity and notice a flare of their skin disease with quently in juvenile dermatomyositis than in the adult
because the location is in the same area that would be ultraviolet light exposure. Children with dermatomyo- form.
covered by a shawl garment. The skin has poikiloder- sitis are much more prone to develop calcinosis cutis Dermatomyositis is a multisystem disorder. Diag-
matous macules and patches. There is a varying amount than their adult counterparts, and approximately 50% nostic criteria have been established by the American
of skin atrophy with telangiectases, mottled hyperpig- of all children with dermatomyositis will develop this College of Rheumatology. They are based on the
mentation and hypopigmentation, and erythema of the feature. Calcinosis cutis manifests as tender dermal presence of clinical, laboratory, and histological find-
involved region. nodules or as calcifications along the muscle fascia. ings. Not all patients have all aspects of the disease, and

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