This is a manifestation of phlebitis.
When the fluid is too cold, too concentrated or contains irritating drugs such as erythromycin, hydrocortisone, chemotherapy drugs, etc., the input into the vein can irritate the lining of the vein and may lead to phlebitis, which manifests as striated red lines along the course of the vein, in addition to local tissue redness, swelling, burning, pain and sometimes systemic symptoms such as chills and fever.