Skin Lesions: Types, Causes, and Treatment

A skin lesion is any skin that is different from the surrounding skin in appearance, texture, and/or color.

There is a wide range of causes of skin lesions, and they are not always a cause for concern.

Some common skin lesions include moles, acne, and eczema.

The treatment for skin lesions depends on their underlying cause.

In many cases, they will go away on their own or can be managed with over-the-counter (OTC) medications or creams.

In this article, I’ll discuss the different types of skin lesions, the differences between malignant and benign lesions, when to contact a healthcare provider and more.

What Are Skin Lesions? 

Skin lesions are any patch of skin that is abnormal in appearance, texture, or color.

There are two types of skin lesions: primary and secondary.

Primary skin lesions appear on their own. Some examples of primary lesions include:

• Nodules: These are solid lesions of skin over 5 millimeters (mm) across.

• Macules: A small, flat area that is different in color.

• Papules: A small dot of red or elevated skin

• Tumors: A large nodule that is more than 2 or 3 centimeters (cm) across.

• Pustules: A small lesion that contains pus

• Vesicles: A small lesion that contains clear fluid

Secondary skin lesions occur following primary lesions.

They usually occur as the primary lesion evolves, either naturally or through you scratching or picking at it. For example, if you pop a pimple (primary lesion), it can scab and form a crust (secondary).

Some types of secondary lesions include:

• Scales: These are dry flakes of skin.

• Crust (scab): A collection of skin, pus, and tissue that forms a hard mass.

• Fissure: This is a crack in the skin surface.

• Scar: A residual mark from a former lesion or injury.

What Do Skin Lesions Look Like? 

Skin lesions are incredibly varied in appearance. Some are raised, while others are flat.

They can be a range of colors and textures, and they can be either round or misshapen.

The most important thing to know about skin lesions is that they look different than the surrounding skin.

Malignant Skin Lesion vs. Benign Skin Lesion 

Most skin lesions are benign and nothing to worry about.

However, some lesions are malignant, which means they are cancerous.

Skin cancer is the most common form of cancer in the U.S. There are two main types: melanoma and non-melanoma skin cancer (NMSC).

When looking at your own skin lesions, it is important to pay attention to color, texture, borders, size, shape, and changes. 

Basal cell carcinomas, a form of NMSC, usually look like light, pearly papules.

Another form of NMSC, squamous cell carcinomas, are rough patches and plaques.

The most severe form of skin cancer, melanoma, is usually darker than the surrounding skin. You can identify a suspicious mole or lesion by using the ABCDE criteria:

• Asymmetric: Cancerous lesions can be asymmetrical, and one side can look different than the other.

• Border: The edges of the lesion that is concerning may be blurry or irregular-appearing

• Color: Generally, cancerous lesions are uneven in color or contain several different shades and colors within them.

• Diameter: If a lesion is larger than ¼ inch, it may be suspicious.

• Evolving: A lesion that changes size or shape may be cancerous.

Causes and Conditions 

There are a variety of causes of skin lesions. Some are very common, like acne, eczema, and moles.

Others, like ringworm and skin infections, require treatment.

Acne 

Acne, also called pimples, is very common, and most of us will experience it at one time or another—especially during our teenage years. 

Pimples are skin-colored papules that are raised from the skin and usually filled with pus.

Too much oil, bacteria, and clogged pores can cause acne. They are especially common in oily areas like the face, back, chest, and shoulders.

Most pimples will go away on their own, but you can treat them with OTC acne medication.

If you have excessive or painful cystic acne, your provider can recommend prescription medications that can help. 

Eczema 

Also known as atopic dermatitis, eczema is a common skin condition that causes red, irritated patches of skin that are flaky, crusted, and dry. Over time, the skin can crack.

You can treat mild eczema with OTC creams and ointments, but if it does not resolve, you should contact your provider.

Herpes Virus

There are two types of herpes: herpes simplex and herpes zoster.

The herpes simplex virus (HSV) causes superficial lesions. They are usually round, raised, and clustered in one spot. 

HSV-1 causes oral herpes, commonly known as cold sores, and other sores on the mouth and face.

HSV-2 causes genital herpes. These can appear on the genitals, buttocks, thighs, and anus.

Herpes zoster, or shingles, happens when the virus that causes chickenpox is reactivated.

If you’ve had chickenpox, you can develop shingles later in life. It is a painful, red rash that looks like a cluster of small round blisters.

Usually, the rash is only on one side of the body. 

Hives 

Hives are usually caused by skin irritation or an allergic reaction. They look like pink or red welts, and they can be very itchy.

Additionally, they can make the affected area swollen and puffy. 

Hives will typically come and go for about 1-2 weeks, depending on their trigger, or until contact with the allergen causing them is removed. 

An antihistamine and cool compresses can help with itching.  

Moles 

Moles are benign lesions of pigment cells. They are usually round, flat, and brown to black in color.

Over time, they can become darker and more raised.

If you have moles, you should watch them for any concerning changes (such as the ABCDE criteria above) and have a health care provider or dermatologist check them once a year. 

Psoriasis 

This skin condition causes itchy, scaly patches that may be red and have a silvery scale to them.

It frequently appears on dry areas like the scalp, elbows, and knees. 

A steroid cream can be helpful, and a dermatologist or primary care provider may recommend prescription treatments if severe.

Ringworm 

Ringworm is a contagious fungal infection that’s spread by skin-to-skin contact. It causes round, “bullseye” patches that look like a round raised circle.  

You can treat ringworm with antifungal medication that is over-the-counter, clotrimazole (Lotrimin). 

If ringworm does not improve with OTC cream, speak with a medical provider. 

Putting a steroid cream like hydrocortisone on ringworm can make it worse.

Contact Dermatitis 

Contact dermatitis is an allergic reaction to an irritant or allergen. Common causes include poison ivy, laundry detergents, and nickel. 

Contact dermatitis may look red or pink and can cause sores, oozing, or blisters as well.

Antihistamines and OTC steroid creams can be helpful, as well as avoiding all fragrances and irritants.

If severe or on large portions of the body, your healthcare provider may recommend oral medication or prescription cream for the allergic reaction.

Epidermoid Cysts 

These are small, hard lumps that form under the skin.

They happen when a skin or hair follicle is disrupted, trapping a small amount of protein and skin cells and forming a bump.

Because epidermoid cysts are benign, they usually don’t need to be treated. If they bother you cosmetically, a dermatologist or plastic surgeon may be able to remove these.

Skin Infections 

There are a variety of skin infections that can cause lesions.

• Cellulitis: This is an infection in the deeper skin layers. When bacteria enter through an injury or skin wound, it can cause an infection, which looks like a red, swollen area that is warm to the touch. It may also cause fever and chills.

• Abscess: This is a large, firm, painful, fluid-filled lesion that is often caused by an antibiotic-resistant bacteria called MRSA or a mix of skin bacteria. These typically require drainage performed in an emergency department or urgent care.

• Boils: These are similar to abscesses but smaller and are tender, red lumps or pustules that are centered around a hair follicle or skin pore.  Some of these may need to be opened and drained; others will get better with warm compresses and an oral or topical antibiotic.
• Impetigo: Impetigo is localized staph or strep bacterial infection. It looks like red sores that can become crusted or develop yellow oozing and flakes. This often affects young and school-aged children and is contagious by direct contact.  It is typically treated with a prescription antibiotic ointment, and severe cases may require an oral antibiotic.

Diagnosis 

When you visit your provider, they will ask questions about your symptoms and medical history.

They’ll also look at your lesion.

If they are unsure of what it is or need to confirm a diagnosis, they may swab the lesion or take a tissue sample for testing. This is a minor procedure that can take place in your provider’s office. 

Treatment 

Treatment for a skin lesion depends on its underlying cause, and some do not require treatment. For example, a benign mole does not need to be treated. 

Medication

You can treat some lesions with topical medications like ointments and creams. These can reduce pain, inflammation, and swelling.

Certain lesions require oral medications. For example, you may need to take oral antifungal medications for ringworm that affects the scalp.

Your provider may prescribe oral antibiotics if you have a more severe skin infection.

Drainage

If a lesion is infected, your provider may recommend drainage.

This is a simple procedure and can usually be done in their office, at an urgent care unit, or ER. 

After that, your provider may prescribe an antibiotic, though this is not needed for all abscesses and boils. 

Removal

Not all lesions need to be removed, but your provider may recommend removing one if it is painful, infected, or may be cancerous.

They may suggest removing:

• Warts
• Some moles
• NMSC
• Melanoma
• Benign growths
• Skin tags
• Actinic keratosis
• Seborrheic keratosis

Some family providers can remove skin lesions- others may refer you to a dermatologist or surgeon.

When To See a Medical Provider 

You can treat common lesions like acne, eczema, and psoriasis with home remedies and OTC medications.

However, you should contact your provider if these do not resolve the lesion. They can help determine the diagnosis and best treatment.

If you have a painful skin lesion, look infected, or aren’t going away, you should see your provider.

Additionally, you should contact them if you have a mole that meets some of the criteria for melanoma.

How K Health Can Help

Did you know you can get affordable primary care with the K Health app?

Download K Health to check your symptoms, explore conditions and treatments, and, if needed, text with a healthcare provider in minutes. K Health’s AI-powered app is based on 20 years of clinical data.