Fungal Infections: Types, Causes and Treatment Options

Fungal infections often start with mild discomfort, an itchy patch of skin, a discoloured nail, or a white coating in the mouth, but it can progress quickly in the absence of treatment. These infections are caused by fungi that naturally exist in the environment and sometimes even on the body, remaining harmless until certain conditions allow them to grow out of control. Warmth, moisture, and damaged skin can create the right setting for this overgrowth, especially in areas such as the feet, groin, or under skin folds. Since fungal infections can appear in different forms and affect various body parts, understanding the underlying cause and recognising the signs is key. This blog covers the main types of fungal infections, how they develop, and the treatment methods commonly used to manage them. Let’s start with the basics.

What are Fungal Infections?

Fungal infections or medically termed “mycosis” are grouped based on the part of the body they affect and the type of fungus involved. The most common infections are superficial and affect areas like the skin, nails, scalp, and mucous membranes. These are mainly caused by fungi called dermatophytes, as well as yeasts such as Candida and certain molds.

In contrast, systemic fungal infections occur when fungi invade deeper tissues, organs, or the bloodstream. These infections are less common but can be severe, particularly in people with weakened immune systems or other health conditions.

Fungi can enter the body through various routes. They may enter through small cuts or breaks in the skin, be inhaled as spores from the environment, or result from an overgrowth of fungi that normally live harmlessly on the body.

Some fungal infections spread directly from person to person, while others develop after contact with contaminated objects, soil, or animals. The way an infection develops depends on the type of fungus, the environment, and the individual's health status.

What are the Types of Fungal Infections?

Fungal infections can be broadly divided into three main types based on how deeply they affect the body: superficial, subcutaneous, and systemic infections.

Superficial Fungal Infections

Superficial fungal infections affect the outermost layers of the body, such as the skin, nails, hair, and mucous membranes. These infections are common and cause symptoms like itching, redness, scaling, and changes in colour or texture. Common examples include:

• Athlete’s Foot (Tinea pedis): Typically affects the feet, especially between the toes, causing itching, peeling, and sometimes burning.

• Ringworm (Tinea corporis): Presents as circular, red, scaly patches on the skin with clearer centres, giving a ring-like appearance.

• Jock Itch (Tinea cruris): Occurs in the groin area, leading to redness, itching, and discomfort.

• Candidiasis: Caused by Candida yeast, it affects areas such as the mouth (oral thrush), genitals, or skin folds, often appearing as white patches or rashes.

• Fungal Nail Infection (Onychomycosis): Results in thickened, brittle, or discoloured nails, which may cause discomfort.

Most superficial infections can be treated effectively with topical antifungal creams or powders, although some may require oral medication.

Subcutaneous Fungal Infections

Subcutaneous fungal infections affect the deeper layers of the skin, as well as tissues beneath the skin. These infections typically occur when fungi enter the body through cuts, puncture wounds, or other skin injuries. They are less common than superficial infections but often more persistent and harder to treat. Examples include:

• Sporotrichosis: Often called “rose gardener’s disease,” this infection enters through small wounds and causes nodules or ulcers on the skin that can spread along lymphatic channels.

• Chromoblastomycosis: Causes wart-like skin lesions that develop slowly and can become chronic.

• Mycetoma: A chronic infection leading to swelling, nodules, and sometimes discharge of fungal material through the skin.

Treatment for subcutaneous infections usually involves longer courses of oral antifungal drugs and sometimes surgical intervention.

Systemic Fungal Infections

Systemic fungal infections occur when fungi invade deeper tissues, organs, or the bloodstream. These infections are rarer but more serious, often affecting people with weakened immune systems. Common systemic infections include:

• Histoplasmosis: Caused by inhaling spores of Histoplasma capsulatum, this mainly affects the lungs but can spread to other organs.

• Aspergillosis: Caused by Aspergillus species, it often affects the lungs and sinuses, causing allergic or invasive disease.

• Cryptococcosis: Caused by Cryptococcus fungi, this infection can lead to severe lung disease or meningitis.

• Invasive Candidiasis: Occurs when Candida enters the bloodstream or internal organs, requiring urgent treatment.

Systemic infections require intensive medical care and treatment with strong antifungal medications, often administered intravenously.

What Causes Fungal Infections and Who is at Risk?

Types of Fungi That Cause Infections

Fungal infections are caused by different groups of fungi, each responsible for specific types of illness.

• Dermatophytes are the most common cause of superficial skin infections such as ringworm, athlete’s foot, and fungal nail infections. These fungi feed on keratin and grow well on skin, nails, and hair.
• Yeasts, especially Candida species, cause infections like oral thrush, vaginal candidiasis, and skin rashes in moist body folds.
• Moulds such as Aspergillus can lead to more serious infections, especially in the lungs, and can also spread to other organs in people with weak immune systems.
• Other environmental fungi including Histoplasma, Cryptococcus, and Sporothrix are found in soil or decaying material and can enter the body through inhalation or broken skin.
  
  

Each type of fungus thrives in different environments and causes distinct infections, ranging from mild to life-threatening depending on the body part affected and the person's immune system.

Conditions That Promote Fungal Growth

Several factors can create favourable conditions for fungi to grow and cause infection.

• Warm and moist environments make it easier for fungi to multiply. This is why fungal infections are more common in areas such as skin folds, feet, and the groin.
• Damaged skin provides an entry point for fungi. Even small cuts or cracked skin can allow infection to set in.
• Inhalation of spores from soil, bird droppings, or decaying vegetation is a common way respiratory fungal infections begin.
• Imbalance in the body’s natural microbes, often caused by long-term use of antibiotics or corticosteroids, can give fungi a chance to grow unchecked.
• Poor hygiene and damp clothing can trap moisture, especially in hot climates, making it easier for skin fungi to take hold.

At-Risk Groups

Certain groups are more likely to develop fungal infections due to underlying health conditions or exposure to risk factors. These include:

• People with weakened immune systems, including those with HIV, diabetes, or cancer
• Individuals on long-term steroids, chemotherapy, or immunosuppressant medicines
• Those who frequently take antibiotics, which disrupt the normal microbial balance
• People with chronic skin conditions or poor circulation
• Individuals exposed to warm, humid environments for long periods
• Infants, elderly, or anyone with thinner or more sensitive skin

Both the type of fungus and the person’s overall health play a key role in how easily an infection develops and how severe it may become.

What are the Common Symptoms of Fungal Infections?

Symptoms of fungal infections vary depending on how deeply the fungus affects the body. Some infections stay on the surface, affecting the skin or nails, while others may go deeper into tissues or organs. Below are the common signs seen in different types of fungal infections.

Symptoms of Superficial Fungal Infections

These affect the outer layers of the body, such as the skin, nails, hair, and mucous membranes. Common symptoms include:

• Itching, redness, or a burning sensation
• Scaly or flaky skin
• Rashes, sometimes with a ring-shaped appearance
• Cracks or peeling, especially between toes or in skin folds
• Thick, discoloured, or brittle nails
• White patches in the mouth (oral thrush) or irritation in the genital area

Symptoms of Subcutaneous Fungal Infections

These develop beneath the skin, often after fungi enter through a cut or puncture. Symptoms may include:

• Firm nodules or lumps under the skin
• Ulcers or slow-healing sores at the site of injury
• Discharge or drainage from affected areas
• Swelling or tenderness around the infection site
• Thickened or wart-like lesions in chronic cases

Symptoms of Systemic Fungal Infections

These involve internal organs and are more serious. They often occur in individuals with weak immune systems. Symptoms can vary based on which organs are affected but may include:

• Persistent cough or chest discomfort
• Fever, chills, and fatigue
• Shortness of breath or difficulty breathing
• Headache, stiff neck, or confusion (if the brain is involved)
• Unexplained weight loss or general weakness

How are Fungal Infections Diagnosed?

Fungal infections can sometimes be identified through a simple physical examination, especially when symptoms are clearly visible on the skin, nails, or mouth. However, many fungal infections resemble other conditions like eczema or bacterial infections, so further tests are often needed to confirm the cause and guide treatment.

Skin Scrapings and Nail Clippings

For fungal infections affecting the skin, scalp, or nails, doctors often take a small sample from the affected area. This may involve scraping off a bit of skin, cutting a piece of the nail, or plucking a hair. The sample is then examined under a microscope to check for fungal cells. In many cases, the sample is also sent to a laboratory for a culture test, which allows the fungus to grow in controlled conditions. This helps identify the exact species, which is useful when symptoms are persistent or do not respond to standard treatment.

Swab Tests

When symptoms involve moist areas such as the mouth, throat, genitals, or folds of skin, a swab is used to collect fluid or discharge. The swabbed sample is tested to detect fungal growth. For example, oral thrush and vaginal candidiasis are often diagnosed this way. These tests can also rule out bacterial infections that may cause similar symptoms.

Blood Tests

Systemic fungal infections, which affect organs or spread through the bloodstream, often require blood tests. These can detect fungal particles or specific antibodies the immune system produces in response to the infection. Blood tests are particularly useful in identifying infections such as candidemia or invasive aspergillosis, especially in people with weakened immune systems.

Imaging Scans

If a fungal infection is suspected in the lungs, brain, or other internal organs, imaging tests such as chest X-rays, CT scans, or MRI scans may be used. These scans help locate areas of infection or inflammation and assess how far the infection has spread. They are often used alongside laboratory tests when diagnosing deep or hard-to-reach fungal infections.

Biopsy

In some cases, especially when other tests are unclear or the infection is deep under the skin or in internal tissues, a biopsy may be needed. A small piece of tissue is removed and closely examined under a microscope. Biopsies provide detailed information about the type and extent of infection, which helps doctors choose the most effective treatment.

What are the Treatment Options for Fungal Infections?

Treatment for fungal infections depends on the type of fungus involved, the severity of the infection, and the part of the body affected. Some mild infections clear up with topical creams, while others may require longer courses of oral or intravenous medication. In certain cases, especially with deep or recurring infections, a combination of treatments may be needed.

Topical Antifungal Medicines

Mild infections that affect the outer layers of the skin, such as athlete’s foot, ringworm, or fungal nail infections, are often treated with antifungal creams, gels, or sprays. These medicines are applied directly to the affected area and help stop fungal growth. Infections in moist areas such as the groin or underarms may also respond well to topical powders that keep the area dry while treating the fungus.

Oral Antifungal Medicines

When topical treatment does not work or when the infection is more widespread, oral antifungal tablets or capsules may be prescribed. These medicines work from within the body and are commonly used to treat conditions like nail infections, vaginal thrush, or severe cases of ringworm. They are also used for some subcutaneous and respiratory infections. The length of treatment depends on the type and severity of the infection and may range from a few days to several months.

Intravenous Antifungal Therapy

Serious fungal infections, particularly those affecting the lungs, bloodstream, or internal organs, often require antifungal medicine given through a drip (IV). This method allows the medicine to act quickly and reach deeper tissues. It is usually needed for patients in hospital, especially those with weakened immune systems or those recovering from major surgery.

How Can You Prevent Fungal Infections?

Fungal infections can often be avoided by following simple hygiene and lifestyle habits. These steps help keep the skin dry, limit fungal growth, and reduce the chance of infection spreading:

• Keep the skin clean and dry: Wash the body regularly with mild soap, and dry thoroughly, especially in areas like the feet, groin, and underarms where moisture can build up.
• Wear breathable clothing and footwear: Choose cotton or other natural fabrics and avoid tight clothes that trap sweat. Use open or ventilated shoes and avoid walking barefoot in public showers or pools.
• Avoid sharing personal items: Do not share towels, socks, shoes, nail clippers, or combs, as fungi can spread easily through contact with contaminated items.
• Maintain good nail and skin hygiene: Trim nails short and keep them clean. Moisturise dry or cracked skin to prevent small breaks where fungi can enter
• Change out of damp clothing quickly: After exercise or swimming, remove wet clothes promptly to reduce the risk of fungal growth in skin folds or between toes.
• Manage health conditions and immunity: Keep blood sugar levels under control in diabetes, and take extra care if on antibiotics or immune-suppressing medicines, as these can make the body more prone to fungal infections.

Consult Today

It’s easy to think of fungal infections as something minor until they keep recurring or stop responding to creams that initially worked. Some deal with the same patchy rash returning again and again. Others face nail infections that won’t clear, even after months of trying home remedies. A few may not realise that what seems like tiredness or a cough is actually linked to something deeper inside the body. These situations are not uncommon, and they don’t have to be faced alone. At Max Hospital, dermatologists and infectious disease specialists understand how stubborn and frustrating fungal infections can be. If something hasn’t felt right for a while, or if symptoms are getting in the way of daily life, consider making time for a proper consultation. Max Hospital is here to help take that next step.