What Causes Cellulitis In The Legs? Science-Backed Treatment

What Causes Cellulitis In The Legs? Science-Backed Treatment

Table of Contents


Cellulitis belongs to the group of dangerous bacterial infections that directly target the deeper layers of the skin: the dermis, or the second layer of skin, and subcutaneous tissue, or the fat and connective tissue that make up the lower layer of the skin. Cellulitis can occur anywhere on the body.

In adults, it is most common in the lower legs. In the field of children, cellulitis often affects the face and neck. More than 14.5 million people in the United States develop cellulitis each year. 

“Cellulitis is literally inflammation of the skin,” says Dr. Tsippora Shainhouse, a dermatologist in the Los Angeles area and a clinical instructor at the University of Southern California. The good news is that cellulitis is usually not contagious.

“It usually appears on the skin as an enlarging pink or red patch that feels warm and hard and sometimes to the touch,” says Dr. Shainhouse.

Cellulitis can start with any scratch in the skin, like a small scratch or insect bite, which allows bacteria to penetrate the deeper layers of the skin. 

It is rare in healthy young adults. Cellulitis is common in the elderly and people with weakened immune systems, chronic skin diseases that cause cracks in the skin, elevated blood sugar levels, or obesity.

Oral antibiotics and Systemic antibiotics or, in acute cases, intravenous antibiotics are the most important things in healing cellulitis. The important consideration is that Because cellulitis affects the deep layers of the skin and tissue, topical antibiotic ointment is not effective in treating cellulitis.

Left untreated, cellulitis can spread to the bloodstream and lymph nodes and quickly become life-threatening.

Due to the serious nature of cellulitis, it’s important to seek medical attention if you’re experiencing symptoms—even if you’re not sure it’s what you have.

You should know before reading.

Cellulitis is not the same as cellulite. Cellulite is a cosmetic point in which fat deposits are formed through the connective tissue of the skin and causes the appearance of organs and lumps in the thighs and buttocks. It is not an infection and poses no risk to patients who have it.

Classification and types of cellulitis

Cellulitis is known as inflammation of connective tissue and skin. Each of the dermal and subcutaneous layers of the skin is involved in this inflammation. This inflammation may be limited to one spot (local) or may spread over a wide area (diffuse). 

In some cases, the inflammation is localized at first but later spreads, especially in the absence of treatment. Cellulitis is usually classified based on the site of infection and underlying cause. There are primarily two main types of Cellulitis:

  1. Uncomplicated cellulitis: This is the most common type of cellulitis and usually occurs on the surface of the skin. It is usually caused by bacteria entering through breaks in the skin, like wounds, cuts, or insect bites. Streptococcus and Staphylococcus aureus are the most common bacteria responsible for uncomplicated cellulitis.
  1. Complicated cellulitis: This type of cellulitis involves deeper layers of skin and tissue and may be associated with underlying conditions or risk factors that complicate the infection. Complications can include infection in areas with poor blood supply, such as the feet (diabetic foot cellulitis), or infection in people with weakened immune systems. Complicated cellulitis may require more aggressive treatment and, if left untreated, can cause more life-threatening complications.


While these are the primary types of cellulitis, healthcare providers may classify cellulitis based on factors such as the specific bacteria involved, the presence of underlying conditions, or the anatomical location of the infection.

Cellulitis symptoms

Despite the similar names, Cellulitis is not related to Cellulitis, which is an appearance in which wrinkles are formed under the skin due to the underlying fat layers. Symptoms of cellulitis include:

  • skin redness
  • Warmth to the touch
  • Stiffness and pain
  • swelling
  • Fever.
  • Red spots.
  • Dimpled skin


The skin may sometimes appear blue, which depends on its causes. Red lines spread from the center of the infection to the surrounding area, indicating the infection has entered the blood. If this happens, high temperature, sweating, chills, and other flu-like symptoms appear.

You may not feel warmth or pain until you touch or press on the infected area. Some people develop other symptoms before the change in skin appearance, such as chills and fatigue.

In more acute cases, additional clinical features may be present, including blister formation, pustules (bumps on the skin containing pus), and necrosis (decomposition of the skin).

A severe infection can cause cold sweats, nausea, difficulty thinking, rapid heart rate, and low blood pressure.

Cellulitis usually does not go away on its own.

Autopsy of causes

Cellulitis is commonly caused by various bacteria, mostly staphylococci and streptococci, that live on the skin. These bacteria attack under the skin through abrasions and cuts, infect the tissues under the skin, cause an inflammatory response, and thus cause cellulitis.

Staphylococcus (“staph”) bacteria on the skin can also cause boils or pus-filled cysts that develop in hair follicles or sebaceous glands, and staphylococcus and streptococcus (“strep”) bacteria can cause impetigo. A highly contagious disease that causes scaly, red sores, usually on the face, arms, and legs.

While STAP and STREP are harmless on your healthy skin, any open wound on your body—including a burn, surgical wound, or even a pimple—can put the bacteria at risk for cellulitis.

Of course, most people will avoid many minor skin sores throughout their lives and never develop cellulitis. However, certain conditions put people at risk of cellulitis. Such conditions include:

  • Advanced age, which is associated with a weak immune system, can be one of the causes of cellulitis.
  • Another common cause is a disease that disrupts the immune system, such as autoimmune diseases, diabetes, cancer, and AIDS or HIV.
  • Use of drugs that suppress the immune system.
  • Injecting illegal drugs.
  • Impaired lymphatic drainage.
  • Overweight or obesity.

If you have a skin condition such as eczema or athlete’s foot, it may cause dry, itchy, and cracked skin and create an entry point for bacteria.

Having had cellulitis once puts you at a higher risk of getting it again.


In short, this sudden disease, which can cause concern due to a change in shape that looks dangerous, has various causes, the most common causes of which are:

  • Entry of bacteria through cracks in the skin

In the first group of causes, bacteria such as streptococcus and staphylococcus aureus are the main culprits of cellulitis. They can enter the skin through cuts, wounds, scrapes, insect bites, surgical incisions, or other breaks in the skin barrier.

  • Getting a new tattoo

One serious cause that may increase the risk of cellulitis is getting a new tattoo. People who have previously been diagnosed with cellulitis have a higher risk of developing it.

  • Skin diseases

Certain skin conditions that cause dry and cracked skin, such as eczema, athlete’s foot, or psoriasis, can increase the risk of cellulitis by creating entry points for bacteria.

  • Injury or trauma

Any trauma to the skin, such as a cut, burn, or puncture wound, can create openings for bacteria to enter and cause infection.

  • Weak immune system

Individuals with debilitated immune systems due to conditions such as diabetes, HIV/AIDS, cancer, or suppressive medications are more susceptible to infections such as cellulitis.

  • Blood circulation problems

Poor circulation, often seen in conditions such as venous insufficiency or peripheral artery disease, can impair the body’s capability to fight infections and may contribute to Cellulitis, especially on the lower extremities.

  • Lymphedema

Lymphedema, a special circumstance characterized by swelling due to blockage or damage to the lymphatic system, can increase the risk of cellulitis by impairing the body’s ability to clear bacteria and other pathogens from the affected area.

  • Invasive methods

Certain medical procedures, such as surgery, catheter placement, or injections, can introduce bacteria into the body and increase the risk of cellulitis, especially if proper hygiene and sterile techniques are not followed.

Misunderstanding in diagnosis.

A doctor can usually diagnose cellulitis by testing the skin, although blood culture, blood tests, and a are used to confirm the diagnosis.

“Some of the most common cellulitis are venous stasis dermatitis, contact dermatitis, eczema, allergic reactions to insects, dyspnea, deep vein thrombosis (DVT), phlebitis, and gout,” says Shanehouse.

It is important to avoid bacterial infection, which can quickly destroy the underlying tissue. This condition is commonly called “flesh-eating disease.”

Here’s a closer look at a few skin conditions that can be mistaken for cellulitis:

Venous stasis dermatitis is this type of redness and swelling of the lower leg due to poor blood circulation. It usually affects both feet and is accompanied by rough and itchy skin.

Allergic contact dermatitis occurs in a situation where the skin is in contact with an allergen, like certain metals or poison ivy. The skin will become red, swollen, and yellow, but this type of reaction does not usually cause a fever. Often, cases of itchy skin form dermatitis in the form of an allergen – for example, a circular rash on the wrists can be mistaken.

Eczema atopic dermatitis causes itchy, red, or scaly skin, and sometimes there are rashes that are oozing and crusty. It can happen anywhere on the body, and it doesn’t happen in the feet.

Shingles, which are created by the chicken pox virus, cause epoxy swelling, a painful rash that is usually seen as a row of blisters. This complication does not occupy a specific part of the body and can occur in any part of the body While it affects one side of the body during infection.

Tinea Pedis is also known as athlete’s foot. This common fungal infection typically causes red, itchy, scaly skin, and sometimes blisters and cracked skin on the feet.

Gout is a complication characterized by the accumulation of uric acid crystals in the joint, along with pain, swelling, and stiffness. Gout can also affect the skin over the joint, making it red and warm to the touch.

Deep vein thrombosis, which, in fact, is a blood clot or thrombus in a deep vein of the leg, can lead to swelling, pain, and warmth. Like cellulitis, deep vein thrombosis commonly occurs in only one leg at a time. 

Phlebitis, also known as phlebitis, is inflammation in a vein that causes pain, redness, swelling, and warmth. Phlebitis can be caused byy deep vein thrombosis and varicose veins. If you experience symptoms of phlebitis, you should seek medical help.

Lipodermatosclerosis indicates the changes in the skin of the lower legs by inflammation of the fat layer under the skin. The skin may be red and harder and darker than usual. The leg itself may swell, and the condition may be painful. One or both legs may be affected.

Cellulitis treatment

The good news is cellulitis responds quickly to treatment. Your doctor may prescribe medication for 10 to 14 days, and you should begin to feel better within a few days of starting the antibiotic – although you should make sure you take all the pills prescribed. The period of treatment depends on the severity of the infection.

Treatment for cellulitis on the legs usually includes antibiotics to eliminate the bacterial infection and may also include measures to manage symptoms and underlying risk factors. Here are common treatment options:

  1. Antibiotics: Antibiotics are the cornerstone of cellulitis treatment. The choice of antibiotic and the duration of healing depends on factors such as the severity of the infection, the suspected bacteria causing the infection, and any underlying disease. Oral antibiotics are commonly prescribed for mild to moderate cases, while severe or complicated cellulitis may require intravenous (IV) antibiotics given in a hospital setting.
  1. Pain controlling: Over-the-counter pain relievers like acetaminophen or ibuprofen can help decrease the pain and fever associated with cellulitis. In some cases, pain medication may be necessary, especially if the infection is severe or causing significant discomfort.
  1. Elevation: Elevating the injured leg above the level of the heart can help reduce swelling and improve circulation, which may aid the healing process. When resting or sleeping, place the leg on pillows or cushions to increase fluid drainage and reduce swelling.
  1. Compression: Compression stockings or bandages may be recommended to help improve circulation and prevent swelling in cases where venous insufficiency or lymphedema contribute to cellulitis. However, compression should be used with caution and under the guidance of a healthcare professional to avoid worsening the infection or causing tissue damage.
  1. Wound Care: Proper wound care is essential to prevent secondary infections and promote healing. Keep the affected area clean and dry, and use topical antiseptic ointments or dressings as directed by your doctor.
  1. Management of underlying conditions: If cellulitis is associated with underlying diseases such as diabetes, venous insufficiency, or lymphedema, effective management of these conditions is very important to prevent recurrent infections. This may include lifestyle modifications, medications, or other interventions to control symptoms and reduce the risk of complications.


In most cases, you take the oral antibiotic home. But if you have severe cellulitis, you may need intravenous antibiotics and hospital admission. The average hospitalization period of a patient for the treatment of cellulitis is more than a week.

If you are taking an oral antibiotic, continue to monitor your symptoms. As a general rule, your symptoms should improve, not worsen. If symptoms do not improve after three days of treatment, consult your doctor immediately.

If you have had more than three or four bouts of cellulitis in the past year, your doctor may prescribe a low-dose antibiotic as a long-term preventative measure.

If you get cellulitis again after starting maintenance therapy, your doctor may need more testing to determine the main cause of your infection, or you may need to see an infectious disease specialist.


What are the complications of untreated Cellulitis?

If cellulitis is left untreated, it will lead to some serious medical situations, like:

  • Infective endocarditis ( The layer of tissue that forms the lining of the heart chamber)
  • glomerulonephritis (kidney infection)
  • lymphadenitis (infection of the lymph nodes)
  • Another important complication of this infection is that it spreads to your bloodstream, and at that time, the infection is life-threatening.


You can increase your chances of coping with complications by doing the following:

  1. See your doctor if you have signs or symptoms of cellulitis.
  2. Take your prescribed antibiotics, and do not stop the original medication.
  3. Tell your doctor if your symptoms do not improve within three days of starting antibiotics.
  4. Get enough rest to help your body heal faster. If you have cellulitis in your legs, increase rest to reduce swelling.


How to prevent cellulitis

One of the best strategies to prevent cellulitis is to perform first aid if the skin is injured.

For a small cut or scrape, generally clean and cover the area yourself and your partner.

But if you have a deep (¼ inch or deep) or large cut, a puncture wound, an animal or human bite, a burn or scratch over a large area of the body, or a wound that bleeds after 10 or 15 minutes of direct pressure on the wound You should seek medical help from your doctor, emergency department, or urgent care center.

The first step for a minor skin injury is as follows:

  • Try to stop the bleeding by giving pressure, preferably with a clean tool like a cloth.
  • Wash the wound to eliminate dirt and debris. Use warm, soapy water if available. If you are not close to modern plumbing, use the cleanest water you can find to thoroughly wash the wound. If you cannot remove all the impurities from the wound, you should find a doctor to clean the wound.
  • Dry the injury and apply a thin layer of a topical antibiotic ointment, if necessary.
  • In order to keep the wound clean and sterilized, close it with a sterile bandage. It reduces the risk of dirt and bacteria getting into the wound.
  • Change the bandage every day until the wound heals.


Special precautions for people with diabetes

People with diabetes, Dr. Adalja says, “must take good care of their feet and treat even minor skin problems. Athlete’s foot (fungal infection on the foot) is one of the causes that can make the skin susceptible to bacterial infection. So it should be treated quickly. Also, they should receive routine daily care.

  • Diabetic foot care

If you have diabetes, check your feet daily for redness, hot spots, pressure marks, or shoe wear. To prevent chapping, apply moisturizer to your feet, but avoid moisturizer between the toes. Additionally, keep your toenails and fingernails trimmed to prevent scratching.

  • Reduce the risk of cellulitis.

Addressing risk factors for cellulitis can also help prevent it. Such possible actions include:

    • Lose weight if you are overweight.
    • Quit smoking if you smoke.
    • Quit alcohol.
    • Discover an infected wound.


Even with the best help, infection can still occur. In this case, early detection is the key to avoid serious complications. Symptoms of an infected wound include:

    • Increased redness and pain.
    • Fluid oozing or blisters at the wound site.
    • swelling
    • tenderness
    • itching


In conclusion, understanding the causes of cellulitis in the legs is crucial for effective treatment and prevention. By addressing factors such as skin injuries, compromised immune systems, and circulation issues, individuals can take proactive steps to decrease their risk of developing cellulitis. 

Additionally, science-backed treatments, including antibiotics, pain management, and wound care, play a vital role in managing cellulitis effectively. 

Remember to find medical attention promptly if you suspect cellulitis, as early intervention can prevent complications and promote a speedy recovery.

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Author and specialist

Dr. Majid Zahrabi,


  • Board Certified Neurosurgeon
  • DHA certificate holder
  • Plantation certificate holder, France
  • Certified holder of Discogol, France
  • A pioneer in the non-surgical treatment of disc herniation in the Middle East and CIS countries.
  • Under the training and coaching of Professor Jacques Theron (founder of Discogel Therapy) since 2008
  • More than 400 successful cervical and 1300 lumbar discogel injections
  • Trained and certified several neurosurgeons and spine surgeons in the Middle East and CIS countries for the treatment of Discogel
  • Strong belief in patient-centered care planning and participation
  • Neurosurgeon and spine surgeon at Imam Khomeini and Amir Mazandarani Hospital, Sari, Iran, with more than 430 surgeries annually, 2000-2011
  • Neurosurgeon and spine surgeon at Farmaniyeh, Nikan and Yas Sepid Hospital, Tehran, Iran, with more than 400 surgeries annually, 2011-2012
  • Neurosurgeon at Iranian Hospital, Dubai, 2022-2023
  • Since 2015, he has been working as a reference doctor for the treatment of intervertebral disc herniation with Discogel and has trained many doctors of spine-related specialties in various countries of the Middle East and CIS in person/practically and online.



  • Individual training sessions under the direct supervision of Professor Jacques Theron in Discogel treatment, 2008-2020
  • Training sessions under the supervision of Professor Thierry Boye on spinal implants, 2007
  • Participation and presentation in several national and international medical and neuro-spinal conferences
  • Board certificate by Iran Neurosurgery Board, 2001
  • Neurosurgery assistant training course, Isfahan University of Medical Sciences, Isfahan, Iran, 1996-2001 (In 2001, he graduated from Isfahan University of Medical Sciences with the first rank in the country.
  • His thesis the titled:The Application of human amniotic membrane in repair of dura matter in dogs.” ( It was happening for the first time in the world. )
  • General medical education, Tabriz University of Medical Sciences, Tabriz, Iran, 1984-1993


Published books:

  • CT scan of the brain for doctors
  • Etiology and treatment of painful spine disorders
  • Atlas of diagnosis, prevention, and treatment of spine disorders
  • The most common mistakes in the treatment of spinal disorders
  • Reading brain CT scan in simple language (3rd place in the book of the year)
  • Treatment of head and spine injuries

Publications and articles:

  • Bacteriostatic and bactericidal effects of DISCOGEL® (https://www.researchgate.net/)
  • Muscle recovery, reduction of pain, and improvement of movement strategies in patients with lumbar discopathy after injection of Discogel.
  • The article on the initial results of the treatment of intervertebral disc herniation with discogel injection, which won the second-best poster rank at the Pan Arab International Congress of Interventional Radiology (March 14-16, 2015) and was accepted for presentation at the Chicago Pain Congress.
  • The use of human amniotic membrane in dura mater repair in dogs, a study for the first time in the world.



  • Annual Congress of Physiotherapists of Iran, 2019
  • Chicago International Pain Congress, 2019
  • Iran International Pain Management Congress, 2018
  • Annual Congress of Physiotherapists of Iran, 2018
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Armenia for orthopedic specialists and neurosurgeons, 2017
  • First Live Workshop and Seminar on Minimally Invasive Disc Therapy (DISCON), 2017
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Azerbaijan for orthopedic specialists and neurosurgeons, 2016
  • Seminar of Iranian official managers, 2016
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Tajikistan for orthopedic specialists and neurosurgeons, 2016
  • International Neurological Intervention Congress in Iran, 2014
  • Educational seminar for nurses on treatment approaches for head and spine trauma, 2014
  • Educational seminar for general practitioners on treatment approaches for head and spine trauma, 2014
  • Speech at the Retraining Seminar for General Practitioners and Specialists in Dubai (Discon) in 2017
  • Speech in the internal retraining courses of Irani Hospital, Dubai
  • Holding lecture sessions and practical workshops on the treatment of intervertebral disc herniation with discogel injection in Azerbaijan, Tajikistan, Ukraine, Oman, and Armenia during the years 2015 to 2021.
  • Giving a lecture and holding a practical workshop for neurosurgeons in Vietnam at Ho Chi Minh City University in 2023

Dr. Majid Zohrabi started treating his patients in Dubai in 2022 and continues his activities in private medical centers in the UAE.