Hi.. Welcome to Healthcare Magic.. I have gone through your query and can very well understand your health concerns.. Pemphigus Vulgaris is an Autoimmune disease which causes blisters over the skin surface as well as Oral mucosa and can very much involuve the gums. The blisters are fragile with a thin covering and can bleed on slight stimulation.. Therefore bleeding on flossing can be due to it.. As you have taken the steroid course and of the signs and if symptoms of disease are not present then bleeding can also be due to gum infection as a result of poor hygiene.. You should consult a dentist and get evaluated as the Oral lesions are many a times diagnostic tool for Pemphigus Vulgaris and if it is recurring you should get it treated again with Steroids.. In case it is poor hygiene Scaling of teeth and antibiotics and gum paint can relieve.. Hope this information helps and thanks for writing to Healthcare Magic.. Of you find the answer helpful please give a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..