There are many reasons for the appearance of red dots on the calves. First, we should consider whether we are suffering from allergic dermatitis or eczema, followed by whether we have been bitten by mosquitoes and insects, all of which can be manifested as red dots on the calves. It occurs in the lower extremities and ankles and is symmetrically distributed. The characteristic manifestation is a palpable purpuric maculopapular rash, bright red to purplish red, which does not fade when pressed. There may be itching and pain, and in severe cases, patients will have fever and arthralgia. 2. Allergic purpura: It is caused by various allergens and invades the skin or other organs with leukocyte fragmentation vasculitis, which mostly occurs in children, along with fever, headache, loss of appetite and other uncomfortable symptoms. There may be a history of upper respiratory tract infection before the onset of the disease; 3. Silicosis dermatitis: It is caused by impaired blood circulation due to varicose veins in the lower limbs and other reasons, and venous stasis leads to increased capillary permeability, causing eczema-like manifestations in the lower legs, which may have erythema, bruises, bruises, etc. The lesions may be scattered along the varicose veins. It occurs in middle-aged and elderly people and is often associated with varicose veins.