A skin lesion is a part of the skin that has an abnormal growth or appearance compared to the skin around it.
Two types of skin lesions exist: primary and secondary. Primary skin lesions are abnormal skin conditions present at birth or acquired over one’s lifetime. Birthmarks are primary skin lesions. Other types include:
- blisters: also called vesicles; these are small lesions filled with a clear fluid. Vesicles can be the result of sunburns, steam burns, insect bites, friction from shoes or clothes, and viral infections.
- macule: freckles and flat moles. Macules are small spots that are typically brown, red, or white. They are usually about one centimeter in diameter.
- nodule: a solid, raised skin lesion. Most nodules are more than two centimeters in diameter.
- papule: a lesion that is rough in texture. Most papules develop with many other papules. A patch of papules is called a plaque. Plaques are common in people with psoriasis.
- pustule: small lesions filled with pus. They are typically the result of acne, boils, or impetigo.
- rash: lesions that cover small or large areas of skin. They can be caused by an allergic reaction. A common allergic reaction rash occurs when someone touches poison ivy.
- wheals: skin lesions caused by an allergic reaction. Hives are an example of wheals.
Secondary skin lesions are the result of irritated or manipulated primary skin lesions. For example, if someone scratches a mole until it bleeds, the resulting lesion, a crust, is now a secondary skin lesion.
The most common secondary skin lesions include:
- crust: a crust, or a scab, is created when dried blood forms over a scratched and irritated skin lesion.
- ulcer: typically caused by a bacterial infection or physical trauma.
- scale: patches of skin cells that build up and then fall off the skin.
- scar: some scratches, cuts, and scrapes will leave scars that are not replaced with healthy, normal skin. Instead, the skin returns as a thick, raised scar. This scar is called a keloid.
- skin atrophy: areas of your skin that become thin and wrinkled from over use of topical steroids or antibiotic creams.
The most common cause of a skin lesion is an infection on or in the skin. One example is a wart. Warts are caused by a virus that is transmitted by touch. A systemic infection (an infection that occurs throughout your body), such as chicken pox or shingles can cause skin lesions all over your body. Some skin lesions are hereditary, such as moles and freckles. Birthmarks are lesions that exist at the time of birth. Still others can be the result of an allergic reaction or sensitivity caused by conditions like poor circulation or diabetes.
Some skin lesions are hereditary. People with family members who have moles or freckles are more likely to develop those two lesions. People with allergies may also be more likely to develop skin lesions related to their allergy. People diagnosed with an auto-immune disease such as psoriasis will continue to be at risk for skin lesions throughout their lives.
In order to diagnose a skin lesion, a dermatologist or doctor will want to conduct a full physical exam. This will include observing the skin lesion and asking for a full account of all symptoms. To confirm a diagnosis, they make take skin samples, perform a biopsy of the affected area, or take a swab from the lesion to send to a lab.
Treatment is based on the underlying cause or causes for skin lesions. A doctor will take into account the type of lesion, personal health history, and any unsuccessful treatments previously attempted.
First-line treatments are often topical medications to help clean, disinfect, and protect the affected area. Topical medication can also provide mild symptom relief to stop pain, itching, or burning caused by the skin lesion. When skin lesions are the result of a systemic infection, such as shingles or chicken pox, patients may be prescribed oral medications to help ease the symptoms of the disease, including skin lesions.
Skin lesions that are infected or extremely painful can be lanced and drained to provide relief. Moles that have become cancerous may need to be removed surgically. A type of birthmark called vascular birthmarks result from malformed blood vessels. Surgery can remove this type of birthmark, too.
Some skin lesions are very itchy and uncomfortable and patients may use home remedies. Some oatmeal baths or lotions can provide relief from itching or burning caused by certain skin lesions. If chaffing is causing contact dermatitis in places where the skin rubs against itself or a piece of clothing, absorbent powders or baby powder can reduce moisture and prevent additional skin lesions from developing.