Red spots on the calf may be caused by allergy, rash, thrombocytopenia, etc., and stomach pain (abdominal pain) may be caused by cold and acute gastroenteritis. 1. Allergy: red spots on the calf with abdominal pain, allergy is mostly considered to be abdominal purpura, need to ask for a detailed history of allergies, itching, etc., and improve the allergens, abdominal CT and other tests. 2. Rash: when the red spot on the calf is a rash, pay attention to the presence of fever, history of eczema, contact with rodents, etc., to exclude the renal syndrome hemorrhagic fever, early childhood acute rash, etc.. 3. Thrombocytopenia: thrombocytopenia is prone to haemostatic dysfunction, and bleeding spots can easily appear all over the body, at this time, it is necessary to improve the blood routine, coagulation function and other tests to clarify the condition. 4. Cold: some people will have abdominal pain when catching cold, mostly accompanied by diarrhea, and the pain will be relieved after applying hot compresses. 5. Acute gastroenteritis: history of unclean diet and cold may appear abdominal pain, diarrhea, vomiting and other symptoms, improve the blood routine, stool routine and culture and other tests can help identify. There are many reasons for red spots on the calves and abdominal pain, so you need to go to the hospital as soon as possible to clarify your condition and actively cooperate with the treatment.