Ticks, like mites, are closely related to spiders. These small creatures, sometimes carried as parasites on the bodies of humans and animals, may transmit disease to humans.
The bites of pajaroello ticks, which are present in Mexico and the southwestern United States, produce pus-filled blisters that break, leaving open sores that develop thick black scabs (eschars).
Most tick bites do not transmit disease and are painless. However, they often cause a red bump and itching at the site of the bite and may cause allergic skin reactions in some people.