Feberblåsor

Feberblåsor, also known as cold sores or fever blisters, are small, painful blisters that typically appear on or around the lips. They are caused by the herpes simplex virus type 1 (HSV-1). In some cases, herpes simplex virus type 2 (HSV-2) can also cause oral sores, though it is more commonly associated with genital herpes.

The initial infection with HSV-1 often occurs in childhood or adolescence and may go unnoticed or cause only mild symptoms like a sore throat or fever, which is where the name "feberblåsor" originates. Once a person is infected, the virus remains dormant in nerve cells in the body. It can be reactivated by various triggers, including stress, illness, fatigue, hormonal changes (like menstruation), sun exposure, or trauma to the affected area.

When reactivated, the virus travels along the nerve pathways back to the skin, causing the characteristic blister to form. Before the blisters appear, many people experience prodromal symptoms such as itching, tingling, burning, or numbness in the area where the sore will develop. The blisters then fill with fluid, eventually break open, and crust over, forming a scab. The healing process typically takes one to two weeks.

Feberblåsor are contagious and can be spread through direct contact with the fluid from an active sore, such as kissing or sharing utensils. Antiviral medications can help shorten the duration and reduce the severity of outbreaks, though they do not cure the infection. There is currently no cure for herpes simplex virus, and the blisters will likely recur periodically throughout a person's life.