Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems that a purple bulb on the outside of the anus with a medical history of having constipation seems to be due to formation of Hemorrhoid or piles.. Hemorrhoids are inflamed and swollen veins that are formed when there is continuous irritation of the veins present in the rectum area and inflammation can lead to pain and bleeding during bowel evacuation.. It can be due to other causes like obesity, vaginal child birth, excess diarrhea and constipation, diabetes etc.. Consult an Anorectal surgeon and get evaluated and a clinical evaluation and anoscopy can be done for diagnosis.. In case if piles is confirmed then you can be advised: -Application of steroid and numbing ointment.. -Sitz bath that is sitting in warm water tub especially after bowels.... -High fibre diet along with laxatives like Polyethylene glycol and stool softeners like Docusate to maintain proper bowels.. -Avoid spicy food and drink plenty of water.. -In case of no improvement with medical treatment you can be advised surgical procedures like Rubber band ligation, sclerotherapy or Hemorrhoidectomy that is surgical removal of the hemorrhoids.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.