Vaginal Hyperplasia

Vaginal hyperplasia is a swelling of the tissue lining the vagina, triggered by the hormonal changes that occur during a female dog's oestrous cycle. The tissue becomes engorged and oedematous, and in some cases a portion of it may protrude visibly from the vulva. This tends to be seen in younger intact female dogs, often during their first or second heat, and the appearance can be concerning for owners who notice a rounded, glistening mass that was not present before. The degree of swelling varies. Some dogs show only mild internal changes that cause no outward signs, while others develop significant protrusion that may be accompanied by licking, difficulty urinating, or occasional bleeding. The condition typically resolves on its own as hormone levels shift through and beyond the heat cycle, though recurrence with future cycles is common. This page explores the patterns that may be observed, the hormonal mechanism underlying the tissue change, the ways it can be assessed, and the range of approaches—from monitoring through a cycle to surgical options for dogs with recurrent or complicated cases.