Bruises from antibiotics?

"Some antibiotics and antidepressants also might be associated with clotting problems. As a result, bleeding from damage to small blood vessels near the skin's surface might take longer than usual to stop. This allows enough blood to leak out under the skin to cause a bruise."

"When is easy bruising a sign of a more serious problem?
Easy bruising sometimes indicates a serious underlying condition, such as a blood-clotting problem or a blood disease. See your health care provider if you:

Have frequent, large bruises, especially if your bruises appear on your trunk, back or face or seem to develop for no known reasons
Have easy bruising and a history of excessive or prolonged bleeding, such as after a minor cut or during a surgical procedure
Suddenly begin bruising, especially if you recently started a new medication
Have a family history of easy bruising or bleeding
These symptoms may indicate:

Low levels of the blood components that help blood clot after injury (platelets)
A problem with how platelets function
Problems with proteins that help the blood clot"

Source: Mayo Clinic