Ecthyma is a rare skin infection that causes serious disease in people with weak immunity. Ecthyma, a severe form of impetigo, is known as “deep” or “ulcerative impetigo” due to its deeper skin penetration, typically caused by Streptococcus or Pseudomonas bacteria.

What is Ecthyma?

This is an uncommonly seen skin manifestation of an underlying infection in your body. Ecthyma is derived from Greek and means “break out”, “ulcer”, or “pustule”, which are characteristic skin symptoms associated with it. It demands prompt management and care as it can result in serious complications without treatment.¹

What causes Ecthyma?

Ecthyma is the reaction of your skin tissue to an infection, especially when your immunity is too low to fight back successfully. It is mostly caused by infectious agents, such as species from the following:²

Bacteria	Staphylococcus Streptococcus Pseudomonas Aeromonas Proteus Escherichia
Fungi	Aspergillus Candida Mucor Rhizopus
Viruses	Herpes Parapoxviruses

Risk Factors for Ecthyma

It mostly develops in people who have compromised immune systems. They cannot fight off the infectious agents in their skin or other parts of their tissues. It is also more common in living conditions that promote the growth of bacteria:³

Medical conditions like diabetes and cancer
Hot, humid weather
Crowded living spaces
Having poor hygiene
Contact with people who have bacterial skin infections
Taking medication that weakens your immune system
Previous skin trauma, e.g., insect bites, dermatitis
Being a neglected child or elderly person
Serving in the military

Types of Ecthyma

There are no official types. However, several skin disorders, including ulcerative and pustular lesions, are common in it.

Classic Ecthyma

It is usually caused by Streptococcus or Staphylococcus bacteria. Even though it is more severe than regular impetigo, it causes less skin damage than ecthyma gangrenosum.

Ecthyma Gangrenosum

Ecthyma gangrenosum is much more serious. Pseudomonas bacteria cause it in immunocompromised people like those who have diabetes, cancer, or HIV. This is associated with a systemic disorder causing skin infection and cell death. It heals with scarring.
Moreover, it is a serious disorder because of how early it progresses and how Pseudomonas is resistant to many antibiotics. Without prompt treatment, it causes more complications as well as death. ⁴

Ecthyma Contagiosum

Contagious ecthyma is a viral disease in cattle. It is also called “orf”. It is sometimes transmitted to humans who come in contact with the infected animals. Orf is caused by Parapoxviruses. It is a rare condition after the eradication of smallpox from the world. However, outbreaks can still occur in less developed countries.⁵

Symptoms of Ecthyma

It is a progressive disease. Lesions vary in size and location. They are around 0.5-3 cm in size and occur on various body parts:

Hands and feet
Limbs
Buttocks
Inguinal region
Genital area

First, a small area of skin becomes inflamed. A blister or pustule develops in this region, which feels itchy. After that, a crust forms over it. An ulcer is formed under this crust.

Image a and b: Ecthyma gangrenosum caused by Staphylococcus aureus in two returning travelers. Image Courtesy: Wound care with antibacterial honey (Medihoney) in pediatric hematology-oncology – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/a-b-Ecthyma-gangraenosum-in-a-leukemia-patient-with-P-aeruginosa-sepsis-a-Early-phase_fig3_7684399 [accessed 29 May 2024]

The crust is hard and painful to remove as it is closely attached to the skin. However, once removed, it reveals a swollen, red ulcer underneath. It often involves nearby lymph nodes and causes pain. Symptoms can include:

Crusty, well-demarcated lesions
Indurating ulcers
Oozing and pus
Open wounds
Pain and discomfort
Itching and scratching
Lymphadenopathy

In ecthyma gangrenosum, the lesions are gangrenous and necrotic. They occur more commonly in areas with skin folds.⁶

Complications of Ecthyma

It has several complications, all varying in severity depending on the extent of the disease and the type of causative organism:

Scarring
Cellulitis
Lymphangitis
Lymphadenitis
Gangrene
Post-streptococcal glomerulonephritis
Septic shock and death

How is Ecthyma Diagnosed?

This is not a common disease. Doctors will suspect you have it if you have a regular, crusty skin rash and give a history pointing to any form of ecthyma. They also look for red flags like gangrenous wounds, which indicate ecthyma gangrenosum.

History & Physical Exam

Doctors can suspect you have this condition based on any risk factors in your medical history, especially if you have a known history of being immunocompromised. They will also ask questions to determine the severity of your disease to start the right antibiotic treatment until your lab results are released.
A thorough skin and physical exam is also necessary for diagnosing it. Different kinds of ecthyma occur in different places. Deep impetigo often appears on your lower extremities. However, ecthyma gangrenosum occurs in skin folds like your inguinal and perianal regions. Contagious ecthyma (caused by a virus) is usually visible as nodules on your hands.

Lab Investigations

The doctors will run a complete panel of lab investigations to determine the cause of your ecthyma. This includes finding out what organism causes it and, if you have an undiagnosed disease, the underlying medical conditions.

Gram Stain

A Gram test identifies the presence of bacteria by dyeing their walls. A doctor will check fluid samples from the pustules on your skin under a microscope for bacteria. Streptococcus and Staphylococcus stain “positively” and appear red or pink. Pseudomonas stains “negatively” and looks blue or violet. Different antibiotics treat infections caused by different organisms, so Gram stain also helps doctors provide you with the right treatment.

Blood Culture

Blood cultures help detect any bacteria or fungi in your bloodstream. Depending on your history, the doctors will check for different infectious organisms. In addition, bacteremia usually points to more severe disease. This helps doctors give you more rigorous treatment to cure you of ecthyma.
General blood tests help find out the underlying cause. For instance:

Complete blood count (for infections and cancer)
Resting and fasting blood sugar levels, HBA1C (for diabetes)
Serum electrolytes
Tests for common infectious agents for immunodeficiency, such as: HIV, Hepatitis, Tuberculosis

Skin Biopsy

A doctor will take a sample of your skin, 4 to 5 mm deep into its layers. They will then place it in a formalin solution and perform different tests on it. Usually, the results show the type of organism causing the eczema, white blood cells, and debris from damage to the skin.

Tissue Biopsy

Ecthyma gangrenosum can require tissue biopsy. Deeper tissues are sampled and studied. They often show necrosis and hemorrhage.

Urine Culture

In case of suspicion of a Pseudomonas infection, urine samples are also obtained.

Treatment of Ecthyma

As it is mostly caused by bacteria, it is treated with antibiotics. In addition, your doctor will guide you about general measures to heal your skin faster and prevent its recurrence.

Supportive Care

The affected areas are cleaned with soap and water. Doctors will advise you to practice better hygiene and reduce risk factors in your life. They will also ask you to adopt a better diet, especially during treatment:

Using separate towels and personal hygiene products
Showering daily with antiseptic soap
Using soothing, non-irritating emollients to avoid scratching the lesions
Using insect repellants to avoid more trauma to the skin

In addition, hospitalized patients are monitored carefully. Regulating blood pressure and maintaining proper oxygen saturation improves patient outcomes in ecthyma gangrenosum. If you have sepsis, doctors will admit you to the Intensive Care Unit for round-the-clock care.

Antibiotics

Antibiotics are medicines that kill or stop the growth of living organisms like bacteria and fungi. Depending on the causative agent, various antibiotics are used to treat ecthyma.⁷

Topical

Topical antibiotics are applied directly to the skin. They kill the bacteria on the skin, stop further skin damage, and prevent bacteria from penetrating deeper tissues. They need to be applied at least thrice a day after crusts have been cleaned.

A variety of topical antibiotics can be applied to your lesions if it is caused by Streptococcus:

Mupirocin
Fusidic acid
Retapamulin
Ozenoxacin
Minocycline
Bacitracin

Topical antibiotics can improve mild cases. Doctors will administer them alongside oral and IV antibiotics for deeper skin infections and systemic diseases, such as ecthyma gangrenosum.

Oral

Your doctor will recommend oral medications if the condition doesn’t improve with topical antibiotics and is associated with other symptoms of infection, like fever.
Streptococcal ecthyma is treated with oral penicillin, such as dicloxacillin. The medication is usually administered for at least a week. In the case of Staphyocuss aureus, cephalexin is also given, as this bacteria is highly resistant to basic antibiotics.
Many other options are available for advanced disease, drug resistance, and allergies to penicillin. Your doctors may combine a few drugs to treat superimposed infections:

Cefaclor
Cefprozil
Cefuroxime
Azithromycin
Clarithromycin
Roxithromycin
Erythromycin
Co-trimoxazole
Clindamycin
Linezolid
Minocycline
Doxycycline

Ecthyma gangrenosum requires more extensive treatment. It has life-threatening complications and can result in death, so treatment is prompt. Empiric therapy is started right away if doctors suspect you have it, including drugs like:

Piperacillin/tazobactam
Cefepime
Levofloxacin
Imipenem

Intravenous

For widespread systemic infections, the antibiotics are administered through an intravenous route. This way, drugs are injected directly into your bloodstream to kill the organisms. Sometimes, vancomycin is used if the bacteria have become resistant to all other antibiotics and are causing serious disease.

Adjuvant Treatment Options

Other than antibiotics, other drugs and treatment methods may also be used to help you recover from ecthyma, especially if it is serious:

Antifungal agents, e.g., itraconazole, ketoconazole, etc, are used if a fungal agent is a suspected causative organism
Antiviral drugs are given if the infection is caused by a virus, e.g., sometimes treated with cidofovir.
Patients with serious ecthyma gangrenosum with neutropenia often have neutropenia (abnormally low neutrophils). Neutrophils help the body fight against bacteria. A granulocyte colony-stimulating factor can be given to improve neutropenia.
Laser therapy may reduce the appearance of scars once your wounds have healed.

Surgery

Surgery is used to drain deep abscesses of pus and debridement of necrotic tissue in ecthyma gangrenosum. It is often the last resort when your lesions keep spreading and are not responding to any medications. Plastic surgery may also improve the cosmetic appearance of extensive scarring.⁸

Is Ecthyma Contagious?

Ecthyma caused by Streptococcus and Staphylococcus bacteria and orf vrius is highly infectious. It can spread among humans from skin-to-skin contact or contact with secretions and scraping from the skin wounds. Ecthyma gangrenosum is less contagious but much more serious than either of them.

Prognosis for Ecthyma

Ecthyma caused by gram-positive bacteria that respond well to antibiotics has an excellent prognosis. Similarly, contagious ecthyma also has a good prognosis. However, ecthyma gangrenosum has a poor prognosis in immunodeficient people, as 1 in 5 people is estimated to die of the disease and its complications. The mortality rate is as high as 77% in some populations.⁹

Ecthyma vs Impetigo

It is a more serious skin infection than impetigo. It is also called “deep” or “ulcerative” impetigo because ecthyma infiltrates the dermis and causes ulcers, while impetigo is limited to the stratum corenum of the skin. There are many differences between the two.

Ecthyma	Impetigo
Caused most commonly by Streptococcus pyogenes	Most commonly caused by Staphylococcus aureus
Formation of ulcers is characteristic	Pustules rarely become ulcerative
Dark colored crusts	Honey colored crusts
Scarring is more common	Scarring is unlikely
This can lead to major complications	Rarely leads to major complications

Conclusion

In conclusion, ecthyma refers to a number of ulcerative, crusty skin rashes caused by infectious agents. The most common cause is Streptococcus bacteria. Doctors treat it with antibiotics, supportive measures, and sometimes surgery. The choice of antibiotics depends on the causative organism. Ecthyma gangrenosum, a severe form caused by Pseudomonas, can be fatal without prompt treatment. Ecthyma has a good prognosis.

Refrences

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Ecthyma gangrenosum | DermNet. (2022). Dermnetnz.org. https://dermnetnz.org/topics/ecthyma-gangrenosum
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Ecthyma: Understanding This Deep Skin Infection

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