A pyogenic granuloma is a collection of blood vessels that grow quickly and abundantly, often at the site of an injury.
The cluster of blood vessels making up the pyogenic granuloma forms a dark red spot that becomes ulcerated and crusts over. This process usually takes 1 to 2 weeks. It is considered an abnormal healing response. Normally, blood vessels respond with growth to help heal a traumatic site. In this condition, it's as if the response is excessive and doesn't know when to turn off.
The cause of pyogenic granuloma is unknown. It is most common in children and young adults, and may occur during pregnancy. The hormonal changes that pregnant women and children undergo may be a contributing factor.