Purple spots refer to areas of skin with purple discoloration, which may look like bruises in some cases. These can be flat spots, like port-wine stains or purpura, or they can be raised spots or bumps, such as angiomas or keloids.
While some of these purple spots are harmless or may disappear on their own, others may require medical treatment.
Below, you will find 9 causes of purple spots on the skin, along with pictures and treatment options.
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1. Purpura
Purple blotches on the skin can be purpura. Purpura appears due to bleeding into the skin and is sometimes referred to as blood spots. It is not a single medical condition but a sign of several other medical conditions.
Purpura usually appears as flat red or purple spots on the skin. Few purpuras can be raised. If you press on them, they do not fade or become pale. They can appear in clusters and may look like a rash.
Blood spots smaller than 2 mm are called petechiae. Purpura is larger – more than 2 mm. Purpuric lesions larger than 1 cm are called ecchymoses (sometimes referred to as bruises).
Unlike traumatic bruises which appear when we fall or bump into something, purpura can appear without any injury or minor injury.
Causes
Purpura can occur due to various reasons.
Thrombocytopenic purpura occurs due to a decrease in platelets. This can occur due to infections, certain medications, autoimmune destruction, or other systemic diseases like cancer. (Platelets are cells in our blood that are required for normal clotting of blood).
Coagulation disorders involve coagulation factors which are proteins in our blood important for blood clotting. These can be affected by several factors like a systemic disease or medications like heparin and warfarin.
Vascular causes (Any disorder that affects the blood vessels): It includes weakening (such as senile purpura), inflammation (vasculitis like Henoch-Schonlein purpura), or injury of blood vessels.
Treatment
Treatment will depend on the underlying cause and may include:
- Steroids.
- Drugs to suppress the overactive immune system.
- Treatment of any underlying infection.
- Blood transfusion to correct platelet levels.
- Surgery to remove the spleen in a few cases.
2. Infantile hemangioma
A purple mark on the skin can be due to infantile hemangiomas, a type of birthmark that appears at birth or shortly thereafter.
These occur due to the formation of extra blood vessels in the skin. They go through three phases of growth: initially, they grow quickly; this is followed by the plateau phase, in which they stay the same size; finally, in the third phase, they decrease in size.
The two main types of infantile hemangiomas are:
- Superficial hemangiomas: Also known as ‘strawberry hemangiomas,’ these usually appear as red or reddish-purple spots on the skin.
- Deep hemangiomas: These are located deeper within the skin and may appear as skin-colored, purple, or bluish spots.
Mixed hemangiomas can have both of the above components and can appear red, purple, or bluish in color.
Cause
The exact cause is not clear.
Treatment
As the child grows, infantile hemangiomas decrease in size and disappear so they do not require treatment.
If they cause any discomfort, they can be treated with medications like beta-blockers or steroids, laser, or surgical removal.
3. Port-wine stain
A port-wine stain is a type of birthmark that often starts as a flat pink or red spot. With age, this spot tends to enlarge and darken, eventually appearing as a reddish-purple mark.
Over time, it may become raised and the overlying skin can thicken. Although it typically appears on the face, a port-wine stain can develop on any part of the body.
Cause
The exact cause is not known. It occurs due to abnormal blood vessels which are wider than normal.
Treatment
Port-wine stain doesn’t go away on its own. It is usually harmless, but if it causes discomfort or for cosmetic reasons, it can be treated.
The most common treatment is laser and the outcome is best when the spot is treated early.
4. Cherry angioma
Cherry angiomas commonly appear as bright red spots but can also appear purple or reddish-purple in color. They are commonly seen in the ages of 30-40 on the chest, back, and arms.
These bumps consist of proliferating small blood vessels.
Cause
The exact cause is not clear. These are often associated with genetics, aging, hormones, or medication side effects.
Treatment
Cherry angiomas are harmless and do not require treatment unless they bleed or for cosmetic reasons. They can be removed by in-office procedures like laser, freezing, or electrosurgery.
5. Granuloma annulare
Granuloma annulare is categorized into several types, the most common of which is “localized”. This type is typically seen in children and young adults.
It presents as ring-shaped, red, or purple spots on the skin that have a smooth surface. The center of these spots may be slightly depressed. Typically, they do not itch or cause pain.
Cause
The exact cause is not known. The associated factors include infection, insect bites, injury, insect bites, medications, or sun exposure.
It is more common in females and in people with diabetes, thyroid disease, or HIV.
Treatment
These spots usually resolve over time. Treating them may help in clearing them faster.
The common treatments of granuloma annulare include topical steroids or calcineurin inhibitors, oral medications like steroids or antimalarials, steroid injection, freezing, and laser.
6. Keloid
Keloids appear as shiny, soft, rubbery, skin-colored, red, or purple raised spots or bumps. These can be associated with itching.
They are commonly seen on the ears, cheeks, upper back, chest (in the pre-sternal area), or shoulders.
Cause
Any type of skin injury can trigger the formation of keloids. They are thought to occur due to the formation of excess collagen during the process of wound healing.
The risk factors associated with keloids include family history, age under 30 years, or darker skin tone.
Treatment
Keloids can be difficult to treat and may regrow back.
Newer lesions may benefit from using silicone pads or pressure dressings. The other treatment options include topical steroids, intralesional steroid injection, laser, freezing, or surgical removal.
7. Venous lake
A venous lake presents as a soft and compressible, blue or dark purple spot on the lips, ears, neck, or face. It is often seen in elderly people.
Cause
The exact cause of this condition is not known. However, it is believed that chronic sun exposure may be a contributing factor. These spots occur due to the dilation of veins, a type of blood vessel, in the skin.
Treatment
A venous lake is harmless, however, for cosmetic reasons or if it causes discomfort, it can be removed by freezing, laser, electrocautery, or rarely by surgical excision.
8. Lichen planus
Lichen planus is a chronic inflammatory condition that can affect skin, nails, scalp, and mucous membranes.
Cutaneous lichen planus can present as:
- A rash with shiny red or purple spots that are firm on palpation.
- The spots may be crossed by fine white lines called Wickham striae.
- Scaly patches.
The spots usually appear on the wrist, ankles, and lower back and may be associated with itching.
Cause
The exact cause is not clear; however, it is thought to occur due to an autoimmune process where our own immune cells attack the skin.
It is associated with several factors:
- Genetics
- Injury
- Certain drugs
- Systemic viral infections like hepatitis C
- Stress
Treatment
The spots of lichen planus may disappear on their own. The following medications may be prescribed to control symptoms:
- Antihistamines
- Steroids
- Retinoids
- Immunosuppressants
9. Skin cancer
While it’s not very common, in rare cases purple spots may occur due to skin cancer. These may include:
Melanoma
Melanoma is a cancer of melanocytes, the cells which make melanin pigment. They usually appear as light or dark brown irregular spots. However, when present on the sole of the foot, they can appear as purple or bruise-like spots.
In addition, amelanotic melanoma is a type of melanoma that lacks melanin pigment and can appear as a skin-colored, pink, red, or purple spot.
Kaposi sarcoma
Kaposi sarcoma is a type of cancer caused by the human herpesvirus 8 (HHV-8). It typically presents as red or purple, bruise-like spots on the skin.
This condition is most commonly seen in individuals with HIV, those with suppressed immune systems, men of Mediterranean descent, and younger age groups in Africa.
Merkel cell cancer
Merkel cell cancer is a form of cancer that arises from Merkel cells. It can present as flesh-colored, red, pink, or purple spots on the skin.
A number of factors may contribute to the development of this cancer, including exposure to the Merkel cell polyomavirus, sun exposure, and a weakened immune system.
Treatment
The treatment of each will vary and may include local surgical excision, removal of lymph nodes, chemotherapy, or radiotherapy.
When to see a doctor
While some purple spots on the skin are harmless, some may be a sign of serious systemic disease or a skin condition. You should see a doctor if:
- You are not sure what is causing the purple spots.
- The spots cover a large area of the body.
- You have systemic symptoms like fever, difficulty breathing, dizziness, etc.
- The spots are painful.
- There is a visible discharge.
- The spots are growing in size quickly.
- They do not go away in 2 weeks.
Key points
Purple spots on the skin can be blood spots or purpura, chronic inflammatory skin conditions like lichen planus, birthmarks, or abnormal skin growths.
They may go away on their own, however, some of these spots need medical treatment. A doctor can help in identifying the underlying cause behind these spots.
References
- Updyke KM, Khachemoune A. Port-Wine Stains: A Focused Review on Their Management. J Drugs Dermatol. 2017 Nov 1;16(11):1145-1151. PMID: 29141064.
- Lichen Planus. Chen J. 2022. DermNet.
- Venous lake. Oakley A. 2017. DermNet.
- Bishop BN, Lynch DT. Kaposi Sarcoma. [Updated 2022 Jun 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.
Disclaimer: This blog post is for information purposes only and does not replace medical advice.