What is a cherry angioma?
Cherry angioma, also known as a Campbell de Morgan spot, is a common type of benign (non-cancerous) skin growth. It is made up of small blood vessels, giving it a reddish or purplish appearance [1, 2]. The growth is usually round or oval, measuring several millimeters in diameter [1]. Cherry angiomas often grow on the torso, arms, legs, and shoulders [2]. They are particularly prevalent in the older population, becoming more common with age [3].
These growths are not a cause for concern unless they bleed or suddenly change appearance, which may be an indicator of skin cancer [2] - if you notice a growth on your skin that appears odd, is irregular in shape and/or colour and/or is bleeding, it is important to promptly visit a dermatologist or a primary care doctor [2].
As cherry angiomas have a distinct appearance and presentation, diagnosis is fairly straightforward. The diagnosis is made through a physical examination by looking at the growth through a dermatoscope - a device similar to a camera used to look at skin lesions with illumination and magnification. Sometimes, should a more in-depth examination be needed, a doctor may decide to do a biopsy, which involves numbing the area with local anaesthesia and take a small sample of the lesion, or the whole lesion. The tissue is then examined under the microscope, with stains that allow for visualisation of certain molecules that help establish a diagnosis [2].
In some cases especially if there is a need to understand the organisation of blood vessels in the angioma, optical coherence tomography may also be used [4].
Cherry angiomas are harmless, so treatment is done mostly for cosmetic purposes. The treatment is focused on removing the whole lesion, and the procedure is usually very simple and is done in office under local anaeshthesia. Variety of approaches can be used, including cryotherapy (where the lesion is frozen with liquid nitrogen), electrocautery (the lesion is "burned off" with a tool utilising electrical current), or excision (cutting out the lesion). Laser can also be used, as well as sclerotherapy, where a substance that disrupts blood vessels is injected.
What are petechiae?
Petechiae are small coloured spots that appear on the skin, caused by small bleeding under the skin. They most commonly form on arms, legs and stomach, and can form on and around the eyelids and in the mouth.
Petechiae are purple, red or brown, and may change colour as they heal. An easy way to tell whether a coloured lesion on your skin is a rash or petechiae is that petechiae do not change colour when pressure is applied on the skin [5].
Petechiae are formed when capliaries (very small blood vessels) break open and blood leaks into the skin [5]. This can occur due to a variety of reasons, including strenuous activity (for instance, petechiae often appear after childbirth).
Infections and reactions to medications are also common causes of petechiae [5, 6]. Certain haematological conditions including thrombocytopenia, leukemias, some types of anemia, platelet dysfunction, coagulation disorders, and vascular diseases can also lead to the formation of petechiae [6].
What are the differences?
Cherry angiomas and petechiae are both skin conditions, but they have distinct characteristics and causes. Cherry angiomas are noncancerous growths made of blood vessels which present as round, redish or purplish lesions [1, 2].
On the other hand, petechiae are small spots under the skin that are red, purple, or brown. They are caused by bleeding under the skin, when capilaries are ruptured as a consequence of strain or disease. Unlike cherry angiomas, petechiae do not protrude above the skin and are not vascular proliferations [7].
In terms of treatment, cherry angiomas usually do not require treatment unless they bleed or change in appearance. However, some people may choose to remove these through cosmetic procedures or surgery [2]. Petechiae, on the other hand, usually resolve on their own without treatment, but addressing the underlying cause may be necessary [7].