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.