Randy Jacobs, M.D. Patient Education
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Papular Urticaria
A. Definition
Papular urticaria is a skin reaction to flea bites and is a result
of an
immunologically mediated reaction. It usually manifests
as an
intensely pruritic ( itchy ) lesion at the bite site. It is most common
in children
although any body can develop these lesions.
B. How does it begin and what causes it?
The reaction begins with a bite from
a flea such as the cat flea or the
dog flea.
Other insects that can also cause this reaction include mites
and bedbugs.
Most people are unaware of having been bitten until
pruritic lesions develop. These lesions started
out as tender, red
papules (
small raised spots on the skin ) or small blisters. Most
of these
lesions are also very itchy. The papules
or blisters usually
are grouped
and occur in crops. Most of the lesions
occur on the legs
and arms
and sometimes on the lower trunk.
C. How
does it progress?
Because most of lesions are itchy,
they are usually scratched and
subsequently become infected. The infected papules
and blisters
may heal
with resulting raised or depressed scars or change in
pigmentation ( hyper- or hypopigmentation).
D. How is it diagnosed?
It is diagnosed by how it looks on
the skin and can be confirmed
by a skin
biopsy. Cultures of the lesions will
also be taken if the
lesion look
infected to identify any existing bacteria.
E. Treatment
and Prevention
1. Treatment of cats and dogs for fleas.
2. Spraying the household with insecticides to get rid of fleas, mites,
and bedbugs.
3. Topical corticosteroids to decrease the itchiness and oral cortico-
steroids can be given for the more severe or
persistent cases.
4. Oral antihistamines such as Benadryl or Atarax can relieve itch.
5. Antibiotics for lesions that have been infected with bacteria.