Skin Ulcers: What They Look Like, Causes, Types, and When to Seek Care

Published on: July 13, 2026

A skin ulcer is an open sore caused by the breakdown of the skin and sometimes the tissue beneath it. Skin ulcers may develop because of poor blood circulation, prolonged pressure, nerve damage, diabetes, injury, or infection. Unlike an ordinary cut, a skin ulcer may heal slowly, repeatedly reopen, or fail to heal without appropriate treatment.

Skin ulcers can become infected and may lead to serious complications. If you are concerned about a sore that is not healing, call Infectious Disease Associates of Tampa Bay at 813-251-8444 to ask whether an infectious disease evaluation is appropriate. Seek immediate medical attention for severe or rapidly worsening symptoms.

What Are Skin Ulcers?

This is not a very pretty or fun topic to cover. However, we feel that it is necessary to make our readers more aware of skin ulcers. The fact that they affect so many people, especially older populations, brings the seriousness of these conditions to the forefront.

Skin ulcers are open sores frequently associated with poor blood circulation. However, circulation problems are not the only possible cause. Pressure, friction, nerve damage, diabetes, injuries, and certain infections can also contribute to the breakdown of skin and underlying tissue.

If you have poor blood circulation, minor wounds that otherwise would heal quickly may not heal properly, leaving that injury to develop into a painful skin ulcer. These sores and ulcers often become infected if not properly treated. An untreated infection can spread to deeper tissue, bones, joints, and the bloodstream, resulting in a serious condition that requires immediate medical attention.

These ulcers can appear on most parts of the body. Common places include the legs, hips, feet, buttocks, and back. Skin ulcers are more likely to affect elderly people, but they can develop at any age when underlying risk factors are present.

What Does a Skin Ulcer Look Like?

A skin ulcer typically looks like a round or irregular open sore. The outer border may appear raised, thick, or uneven. As the ulcer forms, you may notice discoloration, warmth, swelling, or changes in the texture of the surrounding skin. A more advanced ulcer may look like a crater and release clear fluid, blood, or pus.

Appearance alone cannot determine the type or cause of an ulcer. A healthcare professional may need to evaluate the wound, circulation, sensation, and signs of infection.

Early Signs of a Skin Ulcer

A skin ulcer may begin with subtle changes before an open wound becomes visible. Early signs can include:

• Persistent red, purple, brown, blue, or unusually dark discoloration
• Skin that feels warmer or cooler than the surrounding area
• Swelling
• Tenderness, itching, or burning
• Shiny, firm, soft, or unusually textured skin
• A blister, shallow break, or small open sore
• Clear fluid appearing on the skin, dressing, sock, or clothing

Those with darker skin tones may notice that the affected area looks shiny, blue, purple, gray, or darker than the surrounding skin rather than bright red.

Signs of a More Advanced Skin Ulcer

As a skin ulcer worsens, it may begin to look like a crater. The wound may become deeper and release clear fluid or blood. Depending on its type, cause, and severity, you may notice:

• Swelling
• Redness or other skin discoloration
• Tenderness
• Itchiness
• Pain
• Changes in skin texture
• Raised, thick, or irregular edges
• Clear or bloody drainage
• Yellow or green pus due to infection
• A foul odor
• Yellow, gray, brown, or black tissue
• Exposed fat or deeper tissue

Some ulcers, particularly neuropathic or diabetic foot ulcers, may not cause significant pain because nerve damage can reduce sensation. A painless wound should not be assumed to be harmless.

Concerned about a nonhealing sore? Call IDATB at 813-251-8444 to discuss whether specialist evaluation may be appropriate.

When Is a Skin Ulcer an Emergency?

A skin ulcer should not be ignored if it is worsening, showing signs of infection, or failing to heal. Seek prompt medical care if you notice:

• Redness or discoloration spreading away from the wound
• Increasing warmth, swelling, tenderness, or pain
• Yellow or green pus
• Increasing or foul-smelling drainage
• Fever or chills
• Red streaks extending from the affected area
• Black, blue, or dying-looking tissue
• New numbness or loss of sensation
• A deep wound or exposed underlying tissue
• A diabetic foot wound that is worsening
• Confusion, weakness, rapid breathing, or other severe symptoms

People with diabetes, poor circulation, reduced sensation, weakened immune systems, or limited mobility should seek medical advice promptly because an ulcer can worsen without producing severe pain.

If symptoms are severe, rapidly spreading, or accompanied by signs of a systemic infection, seek emergency medical care rather than waiting for an office appointment.

Skin Ulcer Risk Factors

Certain risk factors can increase a person’s susceptibility to skin ulcers. It is important to recognize these factors so you can remain vigilant and prepared, both for yourself and your loved ones.

• Pregnancy: Pregnancy can cause hormonal changes. Additionally, increased blood volume may contribute to leg vein problems.
• Cigarette smoking: Tobacco use can damage and harden arteries, disrupting proper blood flow and interfering with healing.
• Limited mobility: Being bedridden, paralyzed, or using a wheelchair can place the skin under constant pressure. Arthritis and leg injuries may also limit movement.
• Increasing age: Age is linked to atherosclerosis and venous insufficiency. Older populations are generally more susceptible to developing skin ulcers.
• High blood pressure: Hypertension, or high blood pressure, can damage arteries and disrupt blood flow.
• High blood cholesterol: High cholesterol can contribute to artery narrowing and oxidative stress, which may interfere with proper circulation.
• Obesity: Obesity can raise the risk of diabetes, atherosclerosis, and increased pressure in the leg veins.
• History of blood clots: People with a history of blood clots may be more likely to experience blood-flow problems.
• Diabetes: Diabetes can affect circulation, nerve function, immune response, and the body’s ability to heal wounds.
• Peripheral neuropathy: Reduced sensation can prevent a person from noticing pressure, blisters, cuts, or other injuries.
• Peripheral artery disease: Narrowed arteries can reduce the amount of oxygen-rich blood reaching the legs and feet.
• Previous skin ulcers: A history of ulcers can increase the likelihood of another ulcer developing in the same area.

What Causes Poor Blood Circulation?

Since poor blood circulation is a major cause of many skin ulcers, it is important to understand the more common causes of circulation issues.

Diabetes

Diabetes causes high blood sugar. High blood sugar can lead to nerve damage called peripheral neuropathy. People who have peripheral neuropathy may lose sensation in their legs and feet. When feeling is reduced, a person may not notice an injury or pain in these areas.

High blood sugar can also slow wound healing. When nerve damage, reduced circulation, and impaired healing occur together, they create conditions in which a skin ulcer can develop or worsen.

People with diabetes should check their feet regularly for cuts, blisters, discoloration, drainage, and open sores, even when there is no pain.

Atherosclerosis

When fat builds up in someone’s arteries, it creates plaque. This formation causes the arteries to narrow. The narrowing and hardening of the arteries is called atherosclerosis, sometimes referred to as arteriosclerosis.

Arteries deliver oxygen-rich blood throughout the body. When arteries become too narrow, they cannot circulate blood effectively. If part of the body does not receive enough blood, skin tissue in that area may begin to break down and form a sore, which can develop into a skin ulcer.

People with diabetes are more likely to develop atherosclerosis and other circulation problems.

Pressure

If someone stays in the same position for too long, constant pressure on the affected area can compress blood vessels. Like atherosclerosis, this reduces healthy blood flow to the skin tissue. If the pressure is not relieved, the tissue may become damaged or die, allowing a pressure ulcer to form.

People with limited mobility may need assistance changing positions and inspecting areas over bones, such as the heels, hips, ankles, elbows, and lower back.

Venous Insufficiency

Venous insufficiency happens when the veins cannot properly return blood from the legs to the heart. Blood can collect in the legs, leading to swelling, heaviness, and changes in the skin.

When swelling becomes severe or persistent, pressure can build in the surrounding tissue and contribute to an ulcer. Varicose veins and a history of blood clots are common causes or risk factors associated with venous insufficiency.

Types of Skin Ulcers

There are four common types of skin ulcers. Each type has a different cause, typical location, and slightly different appearance or symptoms. A medical evaluation is important because treatments appropriate for one type of ulcer may not be appropriate for another.

Decubitus or Pressure Ulcers

Decubitus ulcers are primarily caused by continuous pressure or friction on a specific area of skin. They are also called pressure ulcers, pressure injuries, pressure sores, or bedsores.

Ulcers of this nature often develop in bony areas because of the additional pressure bones place on the surrounding skin and tissue. Decubitus ulcers are most often found on the:

• Back
• Hips
• Buttocks
• Ankles
• Heels

An early pressure injury may appear as persistent discoloration or an area that feels warmer, cooler, firmer, or softer than the nearby skin. As the injury progresses, it may become a blister, shallow sore, or deeper open wound.

Venous Skin Ulcers

Roughly 80 to 90% of leg ulcers have historically been estimated to be venous leg ulcers. These ulcers are largely associated with venous insufficiency, which causes poor circulation in the legs and allows blood and fluid to collect.

This accumulation can create pressure, swelling, and changes in the skin, eventually causing a venous skin ulcer to form. This type of ulcer usually affects the leg between the ankle and knee.

Venous ulcers may appear shallow and irregularly shaped. The surrounding skin may be swollen, itchy, hardened, shiny, or discolored.

Arterial Skin Ulcers

Arterial ulcers, also called ischemic ulcers, occur when atherosclerosis or another arterial condition reduces blood flow through blocked or narrowed arteries.

This type of skin ulcer can be extremely painful. Pain may become worse at night or when the affected leg is elevated or the person is not moving. However, pain levels can vary, particularly when nerve damage is also present.

Arterial ulcers commonly form on the:

• Lower leg
• Feet
• Heels
• Toes
• Outer side of the ankles

These ulcers may have a deep or “punched-out” appearance. The surrounding skin may look shiny, tight, dry, cool, pale, or hairless. Arterial ulcers require medical evaluation because reduced blood flow can interfere significantly with healing.

Neuropathic Skin Ulcers

Neuropathic ulcers are usually caused by nerve damage and may occur alongside narrowed arteries or other circulation problems. They are sometimes referred to as diabetic foot ulcers when they develop in a person with diabetes.

These ulcers typically develop on pressure points of the foot, including the:

• Heels
• Toes
• Bottom of the feet

Because nerve damage may reduce sensation, the affected person may not feel the developing sore. The first noticeable sign might be clear fluid or blood on a sock rather than pain.

Earlier research estimated that nearly 15% of people with diabetes may experience neuropathic foot ulcers. This is a serious, compounding problem for people with diabetes because reduced sensation and impaired healing can allow a small injury to worsen before it is noticed.

Can a Skin Ulcer Become Infected?

Yes. A skin ulcer creates an opening through which bacteria and other organisms may enter the body. Infection may remain near the wound or spread into surrounding skin, deeper soft tissue, joints, bones, or the bloodstream.

Possible complications include:

• Cellulitis
• Abscess formation
• Deep soft-tissue infection
• Bone infection, also called osteomyelitis
• Bloodstream infection
• Tissue death
• Delayed healing
• Hospitalization or surgery in severe cases

Not every ulcer requires antibiotics. Antibiotics treat certain bacterial infections, not the underlying circulation, pressure, or nerve problem that caused the ulcer. A healthcare professional must determine whether infection is present and which treatment is appropriate.

Redness, warmth, pus, odor, fever, or worsening pain may indicate infection. Call IDATB at 813-251-8444 to request an evaluation. Seek immediate care if symptoms are severe or rapidly worsening.

How Are Skin Ulcers Diagnosed?

Diagnosis begins with a medical history and physical examination. A healthcare professional may assess:

• The wound’s size, depth, location, edges, color, and drainage
• The condition of the surrounding skin
• Signs of infection
• Blood flow to the affected area
• Sensation and possible nerve damage
• Diabetes and blood sugar management
• Mobility, pressure, footwear, or repetitive friction
• Previous ulcers, blood clots, or vascular conditions

Depending on the symptoms and suspected cause, additional evaluation may include blood tests, circulation testing, imaging, or a wound culture. If a deep infection or bone infection is suspected, more extensive testing may be necessary.

How Are Skin Ulcers Treated?

Treatment depends on the ulcer’s cause, location, severity, circulation, and whether infection is present. There is no single treatment that is appropriate for every skin ulcer.

A treatment plan may include:

• Cleaning and protecting the wound
• Appropriate wound dressings
• Removing pressure from the affected area
• Specialized footwear or offloading devices
• Repositioning for people with limited mobility
• Compression therapy when medically appropriate
• Treatment to improve circulation
• Diabetes and blood sugar management
• Removal of damaged or dead tissue when appropriate
• Antibiotics for a diagnosed bacterial infection
• Intravenous medication for certain serious infections
• Coordinated care with wound, vascular, podiatric, surgical, primary care, or infectious disease specialists

Compression should not be started without professional guidance because it may be unsafe for some people with severely reduced arterial circulation.

What Should You Avoid Doing at Home?

If you think you have a skin ulcer:

• Do not cut away damaged or dead-looking tissue yourself.
• Do not use leftover antibiotics.
• Do not apply harsh disinfectants or unapproved products without medical guidance.
• Do not assume a painless wound is harmless.
• Do not continue placing pressure or friction on the affected area.
• Do not begin compression treatment unless a qualified provider recommends it.
• Do not delay care when the wound is worsening, infected, or failing to heal.

Basic first aid cannot correct an underlying circulation problem, nerve injury, or deep infection. Ask a healthcare professional for wound-care instructions appropriate to the ulcer’s cause.

How Can Skin Ulcers Be Prevented?

Not every skin ulcer can be prevented, but several steps can reduce risk:

• Check the skin and feet regularly for discoloration, blisters, cuts, drainage, or open sores.
• Change positions regularly when mobility is limited.
• Keep skin clean and appropriately moisturized.
• Wear properly fitting shoes.
• Avoid walking barefoot if you have diabetes or reduced sensation.
• Follow your healthcare provider’s diabetes management plan.
• Address swelling and circulation concerns with a qualified provider.
• Avoid smoking and tobacco use.
• Follow professional wound-care instructions.
• Seek medical advice when a wound is not improving.

Skin Ulcer and Wound Infection Care in Tampa Bay

Infectious Disease Associates of Tampa Bay, or IDATB, provides high-quality healthcare services for patients throughout the Tampa Bay metro area. IDATB physicians specialize in diagnosing and treating infectious diseases, including certain complex skin, soft-tissue, and bone infections.

Skin ulcers can have several underlying causes, so care may involve coordination among infectious disease specialists, wound-care professionals, vascular specialists, podiatrists, surgeons, and primary care providers. IDATB’s role is especially relevant when an ulcer has a suspected or confirmed infection, recurrent infection, unusual organism, deep tissue involvement, or possible bone infection.

IDATB has over 30 years of experience treating Floridians with infectious diseases and provides an in-house lab for necessary testing. Patients from Clearwater and surrounding Tampa Bay communities can call to ask which IDATB location and type of care may be appropriate.

Do you have concerns about an infected or nonhealing skin ulcer? Call IDATB at 813-251-8444 to request an evaluation or learn more about available care.

Frequently Asked Questions

What does a skin ulcer look like when it first starts?

An early skin ulcer may appear as persistent discoloration, warmth, swelling, tenderness, or an unusual change in skin texture. A blister or shallow opening may then develop. Appearance varies by ulcer type and skin tone, so a medical examination may be needed for an accurate diagnosis.

How can you tell whether a skin ulcer is infected?

Possible infection signs include spreading redness or discoloration, warmth, swelling, worsening pain, pus, foul odor, increased drainage, fever, or chills. A healthcare professional should evaluate these symptoms. Severe or rapidly worsening symptoms require immediate medical attention.

What is the difference between a skin ulcer and a regular wound?

An ordinary wound usually progresses through normal stages of healing. A skin ulcer heals slowly, fails to close, repeatedly reopens, or becomes deeper because of an underlying problem such as pressure, poor circulation, nerve damage, diabetes, or infection.

Are skin ulcers always painful?

No. Venous and arterial ulcers can cause pain, but a neuropathic or diabetic foot ulcer may cause little or no pain because nerve damage reduces sensation. The absence of pain does not mean the ulcer is minor or safe to ignore.

Can a skin ulcer heal on its own?

Some small ulcers may improve, but many require treatment of the underlying cause. Continued pressure, poor circulation, uncontrolled diabetes, or infection can prevent healing. A sore that is worsening or failing to improve should be evaluated by a healthcare professional.

How long does a skin ulcer take to heal?

Healing time varies according to the ulcer’s type, depth, circulation, infection status, and the person’s overall health. Some ulcers may take weeks or months to heal. Treating the underlying cause and following an appropriate wound-care plan are essential.

Can an infected skin ulcer spread to the bone?

Yes. An infection may spread from an ulcer into deeper tissue or bone, causing osteomyelitis. Deep wounds, persistent drainage, exposed bone, fever, increasing pain, or a wound that does not heal may require additional evaluation.

Which doctor should you see for a skin ulcer?

The appropriate provider depends on the ulcer’s cause. Care may involve a primary care provider, wound-care specialist, vascular specialist, podiatrist, surgeon, or infectious disease physician. IDATB can evaluate certain suspected or complex infections associated with skin ulcers.

Should you cover a skin ulcer or leave it open?

The correct dressing depends on the ulcer’s type, location, drainage, and condition. Do not assume that leaving it open is best. A healthcare professional can recommend appropriate cleaning, protection, and dressing instructions.

When should Clearwater patients contact IDATB?

Patients from Clearwater can contact IDATB if they are concerned about a suspected or confirmed infection, a recurrent wound infection, drainage, fever, a nonhealing diabetic foot ulcer, or possible deep tissue or bone involvement. Call 813-251-8444 to ask whether an IDATB evaluation is appropriate.

Request an Evaluation for a Possible Skin Ulcer Infection

Do not ignore an open sore that is worsening, showing signs of infection, or failing to heal. Early evaluation can help identify the cause and reduce the risk of serious complications.

If you have questions or concerns about infectious diseases or skin ulcers, call Infectious Disease Associates of Tampa Bay at 813-251-8444. Patients from Tampa, Wesley Chapel, Clearwater, and surrounding Tampa Bay communities can contact the team to discuss the appropriate next step.

This article is for general educational purposes and is not a substitute for diagnosis or individualized medical advice. Seek immediate medical attention for severe symptoms or a rapidly worsening infection.