This type of bruise is usually not dangerous and is rarely caused by a serious pathology.
However, in these circumstances, it is necessary to consult a doctor and determine the cause of the bruise:
- The bruise increases in size over time;
- You cannot stop the bleeding easily;
- It is accompanied by severe pain;
- Your nosebleeds are severe or last for an unusually long time;
- You have severe night sweats that soak your clothes;
- You lose an unusually large amount of blood during your period or you notice that there are unusually large clots in your menstrual blood.
The most common causes are:
- Intense physical activity, heavy lifting, exercise;
- Side effects of certain medications;
- Nutrient deficiencies in the body;
- Diabetes;
- Von Willebrand's disease;
- Thrombophilia.
Source:
https://www.healthline.com/health/random-bruising#less-common-causes
