The precursors of a relapse of allergic purpura typically occur in patients after exposure to cold, strenuous exercise, or allergens, manifesting as purpuric rash on the skin. Additionally, some patients may experience gastrointestinal reactions such as nausea, vomiting, abdominal pain, and diarrhea. More severe cases can present with symptoms of allergic purpura and purpura nephritis, primarily characterized by edema and significant proteinuria indicated in routine urine tests. If patients experience the aforementioned symptoms, it is crucial to be vigilant about the possibility of a relapse of allergic purpura and to seek medical attention promptly to prevent further progression of the disease.