lower extremities rash; right ankle swelling; red spots; red spots; inability to walk; Henoch-Schonlein Purpura; rhinorrhea; transient headache; non pitting edema were noted on the right lateral malleolus, which was tender; subcutaneous edema; soft tissue swelling; pain isolated to the lower back; had limited range of motion in all directions secondary to pain; transient, bilateral wrist, ankle, and shin pain; shin pain; abdominal pain; petechial rash extending from both proximal thighs to the dorsi of both feet; Nonpalpable purpura; non pitting edema were noted on the right lateral malleolus, which was tender; This case was reported in a literature article and described the occurrence of henoch-schonlein purpura in a 4-year-old female patient who received Flu unspecified (Influenza vaccine) for prophylaxis.  On an unknown date, the patient received Influenza vaccine. On an unknown date, 72 hrs after receiving Influenza vaccine, the patient experienced henoch-schonlein purpura (serious criteria hospitalization), rhinorrhea (serious criteria hospitalization), abdominal pain (serious criteria hospitalization), headache transient (serious criteria hospitalization), wrist pain (serious criteria hospitalization), leg pain (serious criteria hospitalization), rash (serious criteria hospitalization), ankle swelling (serious criteria hospitalization), red spotty rash (serious criteria hospitalization), swelling (serious criteria hospitalization), unable to walk (serious criteria hospitalization), petechial rash (serious criteria hospitalization), purpura (serious criteria hospitalization), edema (serious criteria hospitalization), tenderness (serious criteria hospitalization), joint range of motion decreased (serious criteria hospitalization), skin edema (serious criteria hospitalization), soft tissue swelling (serious criteria hospitalization) and back pain (serious criteria hospitalization). The patient was treated with ibuprofen. On an unknown date, the outcome of the henoch-schonlein purpura, rhinorrhea, ankle swelling, red spotty rash, swelling, unable to walk, tenderness, skin edema and soft tissue swelling were unknown and the outcome of the abdominal pain, headache transient, wrist pain, leg pain, rash, petechial rash, purpura, edema, joint range of motion decreased and back pain were recovered/resolved.   The reporter considered the henoch-schonlein purpura, rhinorrhea, abdominal pain, headache transient, wrist pain, leg pain, rash, ankle swelling, red spotty rash, swelling, unable to walk, petechial rash, purpura, edema, tenderness, joint range of motion decreased, skin edema, soft tissue swelling and back pain to be possibly related to Influenza vaccine.  Additional details were provided as follows: This case was reported in a literature article and described the occurrence of Henoch-Schonlein Purpura with subcutaneous edema in a 4-year-old female patient, who was vaccinated unspecified influenza vaccine (manufacturer unknown) for prophylaxis.  No information on patient medical or family history or concurrent condition or concomitant medication was reported.  On an unspecified date, the patient received unspecified influenza vaccine (administration route unspecified, dosage unknown; batch number not provided) from her primary care physician. The age at vaccination was not reported but it could be between 3 and 4 years.  On an unspecified date at the age of 4 years, 72 hours after vaccination, the symptoms appeared. According to patient's mother, the patient initially had rhinorrhea (without any other upper respiratory symptoms or sore throat) and mild abdominal pain beginning 3 days prior to presentation. This was followed by a transient headache the next day, which spontaneously subsided. Two days later, the patient complained of transient, bilateral wrist, ankle, and shin pain, and later that evening, the patient developed a rash on the bilateral lower extremities and right ankle swelling. The mother described the rash as initially starting as small red dots that coalesced by the next morning. Ibuprofen was given to the patient without improvement. The morning prior to presenting to the emergency department, the patient started to complain of pain isolated to the lower back and right ankle and had a small area of painful swelling in the lumbosacral area, which made ambulation painful. The patient accompanied by her biological parents presented to the emergency department after the patient's mother noticed a 2-day history of worsening rash and inability to walk. Both parents denied any trauma, insect bites, changes in behavior, appetite, activity, or recent fevers. They also denied any new exposures, dietary changes, or contributory travel or family history. Upon examination in the emergency department, the patient's vital signs were normal, with a blood pressure of 100/60 mm Hg (50th-90th percentile for age). The patient laid in bed comfortably and was alert and oriented. There was a petechial rash extending from both proximal thighs to the dorsi of both feet. Nonpalpable purpura and non pitting edema were noted on the right lateral malleolus, which was tender to palpation and had limited range of motion in all directions secondary to pain. A nonpitting edematous patch approximately 3X2 cm was also noted in the lumbosacral area that was tender to palpation without overriding erythema or induration. Otherwise, the patient's physical and neurologic examination were normal. Laboratory investigations included a urinalysis, complete metabolic panel, and coagulation panel (prothrombin time/partial thromboplastin time/international normalized ratio), which were negative. The complete blood count was normal except for an elevated white blood cell count of 17,580/microL (reference range, 4,800-10,800 /microL) and an elevated platelet count of 692,000/microL (reference range, 130,000-400,000/microL). Inflammatory markers were slightly elevated, with the C-reactive protein level being 0.7mg/dL (reference range, 0.0-0.4 mg/dL) and the erythrocyte sedimentation rate being 25 mm/h (reference range, 0-20 mm/h). An x-ray of the right ankle showed isolated soft tissue swelling at the lateral malleolus. After admission to the pediatric floor, magnetic resonance imaging of the lumbosacral spine was performed, which showed mild posterior subcutaneous soft tissue swelling. Additional laboratory studies were performed including C3, C4, and IgA levels, all of which were normal. Anti-streptolysin O titers and anti-DNAase B titers were not drawn. The patient was diagnosed with Henoch-Schonlein purpura with subcutaneous edema. The patient's pain and immobility remitted within the next 24 hours, as did the petechiae, purpura, and edema of her right ankle and lower back. No corticosteroids were given. Five weeks later, the complete blood count, comprehensive metabolic panel, and urinalysis were repeated, all of which were normal. There had been no recurrences to date.  The case was considered as serious due to hospitalization.  The authors commented "Henoch-Schonlein purpura is an immune complex-mediated leukocytoclastic vasculitis that triggers a multisystem response. In addition, other triggers associated with HSP have been indentified including a wide variety of infectious pathogens, vaccinations (measles/mumps/rubella, pneumococcal, influenza, hepatitis B, and meningitis C), insect bites, and drugs. Subcutaneous, transient, nonpitting edema is a common finding in HSP, especially in the ankles and feet.9 Histopathology from skin biopsies in areas of edema has shown red blood cell extravasation and papillary dermal inflammation, this being due to capillary endothelial IgA deposition causing increased capillary permeability. This could cause rapid soft tissue fluid accumulation which was most likely the cause of our patient's pain and inability to walk. More specifically, in the context of lower extremity petechiae/purpura being considered the sine qua non, for the diagnosis of HSP the finding of subcutaneous nonpitting edema anywhere on the body should be revisited with interrater reliability of this finding determined to see if the specificity of this clinical prediction model can be enhanced".