Overview

Boils, otherwise known as furuncles, are raised bumps on the skin caused by bacterial infection. The bacteria responsible for boil development is called Staphylococcus aureus, or Staph, and penetrates lesions in any surface of the skin.¹ Staph is a healthy component of the human skin microbiome, which causes no harm to its host under normal conditions. However, when a cut or a wound is present, Staph can invade the skin and cause infection.²

Infections, including Staph infections, are particularly detrimental to individuals with immune system disorders. Immune system disorders include conditions which affect the efficient functionality of the cells, tissues, and organs which fight infection (i.e., the immune system). Examples of conditions affecting the immune system include immunodeficiency disease, autoimmune disorders, and allergies.³

This article aims to address the relationship between boils and immune system disorders, as well as the symptoms, management, and prevention of boils. 

Relationship between boils and immune system disorders

Whilst boils can manifest on anyone, individuals with weakened immune systems are more susceptible to the development, and worsening severity of boils.¹ This is due to:⁴

• Weakened defense mechanisms - a compromised immune system has fewer and/or less functional immune cells, meaning when bacteria, such as Strap, infiltrate into the skin, there is a minimal immune barrier to prevent infection
• Delayed healing - where the immune system is weaker, the time taken to fully heal a wound is longer, leaving more opportunity for bacteria to enter and cause infection
• Increased risk of infection - individuals with weakened immune systems are generally more infection-prone. This makes them more susceptible to boils especially when there are cuts and abrasions in the skin

The most common disorders correlated with weakened immune systems are diabetes and HIV/AIDs.⁵

Pathophysiology

How do boils form?

Most boils originate because of bacteria (most commonly Staph) entering the body through cuts and abrasions, but can also gain entry through hair follicles. Staph bacteria then attach themselves to skin cells and hair follicles, where they are able to rapidly multiply due to the warm and moist environment being perfect for bacterial growth.

The first line of response by the immune system, called the innate immune response, begins by recognising Staph-specific patterns on the bacterial surface and causing an immune response. As immune cells begin to accumulate in the hair follicle, the competition between immune cells and bacteria results in a buildup of dead immune and bacterial cells. This buildup is referred to as pus.⁶

Immune system dysfunction and boil formation

When the immune response is impaired, the innate immune response is weakened, leading to little to no recognition of bacterial invasion. This allows the bacteria to multiply rapidly, worsening the infection and leading to the development of a carbuncle.⁴

A carbuncle is a boil with multiple heads. These then manifest into an accumulation of pus, called an abscess. When left untreated, an abscess can cause cellulitis, the infection of surrounding tissues often leading to a fever and worsening illness.¹ Preventing further infection is essential for patients with weak immune systems to prevent the development of life-threatening sepsis. 

Symptoms and diagnosis

Symptoms of boils

A boil is a raised, red, painful, and swollen pus-filled lump that presents on the skin. They are often linked with fevers and swelling of the lymph nodes.^1,5

Diagnostic methods

Boils are most often diagnosed by their characteristic appearance and the description of symptoms provided by the patient. However, further diagnostic tools might be needed for patients with recurring boils, multiple boils, and/or at high risk of complications, such as having a compromised immune system. These further tests include blood tests and swabs of the pus.⁷

Management and treatment

Medical treatment for boils

Boils often heal on their own, however a doctor may prescribe a course of antibiotics to reduce infection or perform a drainage procedure to remove the pus.⁵

Treating underlying immune disorders

Multiple methods can be used to treat immune disorders, depending on the specific condition, for instance:⁸

• Medication, including immunosuppressants, biologics, antibiotics, and anti-inflammatory drugs
• Lifestyle changes, ensuring a balanced diet, regular physical activity, adequate rest, and stress management
• Therapies, such as Intravenous Immunoglobulin, Plasmapheresis, or a Stem Cell Transplant
• Vaccination, to either prevent catching infections or to directly treat the immune conditions

Home and prevention care

There are several measures that can be taken to prevent boil formation, including:¹

• Maintaining a healthy weight by engaging in regular exercise
• Following a balanced and diverse diet
• Avoiding smoking and excessive alcohol consumption
• Regular washing with soap, once daily
• Avoid sharing towels
• Changing clothes regularly, especially after exercise
• Regular medical checkups, especially for individuals with immune disorders
• Staying on top of vaccinations
• Completing the full course of antibiotics for recurring cases

Case studies and real-world examples

Diabetes mellitus, better known as diabetes, is a common autoimmune condition often associated with a weakened and less effective immune system. A 2013 case report, observing 21 diabetic patients with Strap-mediated carbuncles, showed no fatalities and an effective recovery with early treatment using antibiotics, and in some cases fluid drainage.⁹

Summary

The formation of a boil is enhanced in patients with weakened immune systems due to a reduced or lack of mechanisms to fight the bacteria. Whilst boils are usually no cause for concern, early detection for patients with immune system disorders is essential in reducing further infection. To avoid the manifestation of carbuncles, immunocompromised patients should ensure they are managing their condition under instruction of the doctor and raise any further concerns in GP appointments.