Page 142 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-57 Integumentary System

Lichen aureus. Golden-colored macules
PIGMENTED PURPURA and patches are characteristic of lichen
aureus. This is one of the variants of
pigmented purpura.
The pigmented purpuras are a group of idiopathic
rashes that can occur at any age. They are grouped
together because of their similar clinical and histologi-
cal presentations. They are believed to be caused not
by vasculitis but by inflammation of the small cutaneous
capillaries, which produces a capillaritis. The rash is
typically of no clinical significance to the patient, but it
can cause significant cosmetic concern, and the pur-
puras need to be differentiated from other conditions
that can cause similar rashes. The five rashes that
make up the pigmented purpuric family of rashes are Schamberg’s disease. Cayenne
Schamberg’s disease, eczematous pigmented purpura pepper–like petechiae.
of Doucas and Kapetanakis, pigmented purpura of This asymptomatic
Gougerot and Blum, lichen aureus, and Majocchi’s idiopathic rash is almost
disease (annular telangiectatic pigmented purpura). exclusively seen on the
Clinical Findings: These entities are grouped lower legs.
together for many reasons. They are believed by some
to be slightly different manifestations of the same
disease state, and the histopathology of all the variants
is strikingly similar. The pigmented purpuric dermato-
ses are benign and are not associated with any underly-
ing abnormality. They can occur at any age. They are
almost entirely asymptomatic in nature. The true inci-
dence of these conditions is unknown, because they are
often not reported. They are believed to occur very
commonly.
Schamberg’s disease is the most frequently encoun-
tered of the pigmented purpuric eruptions. It almost
universally begins on the lower extremities. It manifests
as tiny (1-mm) cayenne pepper–like petechial macules
of the skin. Over time, a brownish-red hyperpigmented
background forms secondary to the extravasation of red
blood cells and their subsequent breakdown within the
skin to release hemosiderin. The lesions are nonblanch-
ing and nonpalpable. The rash may spread proximally
up the lower extremity but rarely affects other areas of
the body. Most patients are referred to the dermatolo-
gist to rule out vasculitis, which is easily done by not
finding any evidence of palpable purpura. The rash is
almost always entirely asymptomatic, and patients fre-
quently complain only of the appearance. If one sees
widespread petechia, a platelet count should be per-
formed to look for thrombocytopenia. If the platelet
count is normal, a skin biopsy of the upper extremity
or truncal area of involvement should be performed to
evaluate for the very rare form of pigmented purpuric Extravasated erythrocytes and a lymphocytic vasculitis are the
mycosis fungoides. key histological features.
Eczematoid pigmented purpura of Doucas and
Kapetanakis is a rare variant that manifests with pete-
chiae and hyperpigmentation but is also associated with
an overlying eczematous eruption. This form is typi-
cally pruritic and can show secondary excoriations.
Pigmented purpura of Gougerot and Blum is also
known as lichenoid pigmented purpura. Small, light
pink to purple papules form on the lower extremities.
They can be mistaken initially for lichen planus. Biop-
sies of these papules show a lichenoid infiltrate. This
pigmented purpura can be distinguished from Scham-
berg’s disease in that the skin findings are palpable. from hemosiderin deposition. This is a rare form of capillaritis. The infiltrate is predominantly lympho-
There is no true palpable purpura. pigmented purpura that typically starts on the legs and cytic. The presence of hemosiderin is more easily seen
Lichen aureus can be seen at any age and manifests spreads slowly over time. in chronic lesions.
with the presence of multiple tiny, golden-colored Pathogenesis: The pigmented purpuric dermatoses Treatment: There is no agreed-upon standard
macules that coalesce into a large macule or patch. are believed to be caused by capillaritis. The exact etiol- therapy, and withholding therapy is a frequently used
Lichen aureus can occur anywhere on the body and is ogy is unknown. option. Anecdotally, topical corticosteroids may be
solitary in nature. Histology: The histological findings are similar across tried for a few weeks. Oral vitamin C and bioflavonoids
The involved regions in Majocchi’s disease show all variants. Extravasation of red blood cells is promi- have been reported to be successful, again mostly in
annular patches with petechiae and hyperpigmentation nent. The extravasation is seen in the vicinity of the anecdotal reports.

128 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS