Differential diagnoses
Differential diagnoses for HSP depend on the level of specificity with which the triad presents. When symptoms are not typical, abdominal cramping alone may be confused with acute abdomen. Rash may be predominantly in the form of target lesions, and can be mistaken for erythema multiforme, particularly after a suspected drug reaction. Rheumatoid arthritis or systemic lupus erythematosus may be suspected with arthralgias. Idiopathic thrombocytopenic purpura can be distinguished from HSP by platelet count. Trauma or meningococcal septicemia may also be mistaken for the correct diagnosis in the presence of an atypical rash with few accompanying symptoms.
Treatment: Steroids, NSAIDs, and careful monitoring of renal function
Corticosteroids may be administered for severe abdominal symptoms, but they have not been shown to be useful in the absence of such symptoms. Conservative management with NSAIDs is the treatment of choice, and careful monitoring of renal function, even in the absence of renal involvement.1,3,5
Outcome and discussion
Due to the presence of the classic HSP triad in our patient, we deemed a biopsy necessary, and managed the patient with ibupro-fen. One week later, her rash had receded and her microscopic hematuria was gone, but the vasculitis had led to lower-extremity edema. The patient’s feet were painfully swollen, and where the patient had scratched a lesion, her foot exhibited honey crusting and warmth, indicating a probable infection (FIGURES 4 AND 5). Her feet and ankles were so swollen and painful that she had difficulty walking. She was given cephalexin 500 mg 4 times daily for her infection, and was also restarted on oral prednisone at 60 mg daily until she could see the rheumatologist 2 days later. She was also issued crutches.
The rheumatologist agreed that this was HSP and told her that she would need to continue the prednisone for 2 months due to the severity of her cutaneous vasculitis. Within 5 days, the patient’s rash had diminished significantly. She was able to walk with less pain, as her ankle swelling decreased (FIGURE 6).
FIGURE 4
Swollen ankle
FIGURE 5
Probable infection
FIGURE 6
The same patient after 5 days
CORRESPONDING AUTHOR
Richard P. Usatine, MD, University of Texas Health Sciences Center at San Antonio, Department of Family and Community Medicine, MC 7794, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900. E-mail: usatine@uthscsa.edu