Superficial Fungal Infections

Overview:

There are various types of fungi that affect different areas of the body, causing distinct symptoms. Most mild to moderate cases can be treated with topical antifungals, whereas severe cases require oral antifungal medications.

Fungal infections of the skin are a very common occurrence in people of all ages, from babies to adults and the elderly, in healthy as well as immunocompromised individuals. There are various types of fungi, and each causes distinct features, depending on the site of infection.

What Are Some Common Types of Fungal Infections?

Some common types of fungi that affect the human skin are as follows:

1. Dermatophytes or tinea.

2. Candida.

3. Tinea versicolor/Pityriasis versicolor.

Candida and tinea versicolor are normal flora of the skin, but when conditions become suitable, they multiply rapidly, then invade and infect the superficial layer of the skin. They very rarely or never spread into the deeper layers. However, immunocompromised individuals must be careful about them entering the bloodstream and causing severe systemic infections.

Some of the common fungal infections (also called superficial mycoses) according to the site of infection are as follows:

1. Tinea (Ringworm)

• Tinea Capitis - Species of certain dermatophytes, namely, Trichophyton and Microsporum, cause infection of the scalp, eyebrows, and eyelashes. They tend to attack the hair shaft and hair follicles.

Symptoms include scaly, raised, red bumps, broken hair shaft, patches of hair loss, intense itching, redness, and pustules.

The mode of transmission is through contact with affected animals (zoophilic) or humans (anthropophilic). It affects children more commonly than adults.

Treatment includes oral antifungal drugs like Itraconazole, Griseofulvin, etc. Topical antifungals are not effective. However, antifungal shampoo is sometimes prescribed alongside oral medication. Keeping the scalp and hair dry and free of excess sweat and moisture is important in both the prevention and treatment of the fungus. Also, affected individuals should not share their towels and hairbrush with others in order to avoid the spread of infection.

Differential diagnoses are psoriasis, alopecia, and seborrheic dermatitis.

• Tinea Barbae - It is characterized by red crusted plaques, lumps, and pustules around the beard and mustache areas.

Symptoms include kerion-like plaques, itching, loose hair that can be easily pulled out, redness, pain, and pus around lesions.

The mode of transmission is usually through contact with animals (zoophilic), as in the case of cattle farmers, and sometimes from humans (anthropophilic). It exclusively attacks adults.

Mild cases can be cured by topical antifungal cream, but moderate to severe cases require oral antifungals like Itraconazole, Fluconazole, etc. Men should avoid sharing shaving kits and towels with others, particularly in places like the gym, locker rooms, or hostels.

Differential diagnoses include alopecia areata and eczema.

• Tinea Corporis - It is the dermatophyte infection of the trunk and the extremities. The soles, palms, and scalp are usually spared. It is characterized by ring-shaped or annular red lesions which have a raised, scaly border. Most lesions have an area of central clearing, whereas some less common variants tend to have a central zone of hyperpigmentation or raised area of pustules with no central clearing. The latter variant can be confused with psoriasis or erythema multiforme.

Symptoms are red or pink raised annular-shaped plaques or patches with scaly raised border, itching, dry, flaky skin around the lesion, loss of hair on affected sites, highly contagious on person to person contact is common.

Topical Miconazole or Clotrimazole cream is generally used to treat it.

Differential diagnoses are erythema multiforme and guttate psoriasis.

• Tinea Cruris (Jock Itch) - This is a dermatophyte infection of the groin and inner thigh folds. The crease around the genitals is commonly affected.

Symptoms include inflamed patches with sharply defined borders that may spread, burning, and itching around the lesions. There may be oozing from the borders. This mostly affects adult men, but it is not uncommon in women.

Topical antifungal creams such as Clotrimazole or Miconazole are very effective in treating it. Keeping the groin area clean and dry and regular changing of underwear are important preventive measures.

The differential diagnosis is eczema.

• Tinea Pedis (Athlete's Foot) - This is characterized by red, scaly, and itchy patches in the interdigital spaces and soles of the feet.

Symptoms are dry, flaky skin, skin cracking and peeling, itching, maceration. It commonly affects young men.

Treatment is usually with topical antifungal creams like Clotrimazole for four to six weeks. Severe cases require oral antifungals like Terbinafine.

The differential diagnosis is eczema.

• Tinea Unguium (Onychomycosis) - This dermatophyte infection affects both fingernails and toenails. It affects the nail bed and causes separation of the nail from the nail bed.

The nail turns yellow, hard, and brittle and breaks off.

A mild infection can be treated with a topical antifungal cream, but most cases require oral antifungals like Terbinafine and Itraconazole. A toenail infection with this fungus is difficult to treat and requires treatment for three months.

The differential diagnosis is paronychia.

2. Candidiasis

Candidal infections are commonly characterized by red itchy rashes.

Depending on the site of infection, the symptoms are red raised rash, intense itching, cracked skin or maceration, dry, flaky skin, oozing, or discharge.

Common sites of mucocutaneous candidiasis are skin folds like the armpits, neck folds, groin, vagina, oral cavity, anus and perianal region, and the nail bed.

Superficial candidiasis has various names on the basis of their site of infection, such as:

• Oral Thrush - Defined by white patches on the surface of the tongue, palate, tonsils, etc., that are difficult to wipe off. Bad breath and loss of taste sensation may be present. It most commonly affects babies and immunocompromised adults.

Differential diagnoses are coated tongue, leukoplakia, and diphtheria.

• Vaginal Thrush - It is characterized by an itchy whitish vaginal discharge, thick in consistency (cottage cheese appearance) which is usually accompanied by a distinct odor and burning pain during sex and urination. It affects women of all ages.

Differential diagnoses are bacterial vaginosis and chlamydia vaginal infection.

• Intertrigo - It is characterized by a red raised rash with associated bumps and pustules, frequently. There is skin cracking and oozing too.

Differential diagnoses are eczema and miliaria.

• Diaper Rash - Affects the diaper area, usually the perianal skin. It appears as a raised red rash with red bumps along the edges.

• Paronychia - Fungal paronychia is commonly caused by Candida, and it affects the nail fold, area under the nail fold, and edges around the nail. It is characterized by erythema and swelling surrounding the nail. There is a loss of the cuticle, and the nail is discolored. Ridges form on the nail plate. People who spend too much time in the water or indulge too much in water-related activities like dishwashing are commonly affected.

Differential diagnosis is tinea unguium infection (onychomycosis).

Superficial candidal infections are usually treated with topical antifungal creams like Miconazole, Clotrimazole, etc. Systemic antifungals like Fluconazole may be required in moderate to severe cases.

3. Pityriasis Versicolor/Tinea Versicolor

This is a different type of fungus from candida and dermatophytes. This normally lives on the skin, but when conditions are favorable, it reproduces rapidly, causing a characteristic rash.

The factors that favor the growth of pityriasis versicolor are hot and humid environment or weather, excessive sweating, oily skin, and compromised immune system.

Symptoms of infection include a characteristic rash consisting of hypopigmented spots. Smaller spots may coalesce and form patches. These spots may be white, pink, or brown, and they do not tan in the sun. They may be dry, scaly, and itchy. It is frequently confused with vitiligo. This most commonly affects the neck, chest, arms, and back. People often come back from holidays wondering why they have white patches on their bodies that do not tan. It is often because of tinea versicolor.

There are three varieties:

• Hypopigmented - pale or white spots or patches.

• Hyperpigmented - brown macules or patches.

• Inflamed - pink patches or macules.

The affected spots or patches may lose melanin and become pale or white, as in the case of the hypopigmented variant. However, this is usually reversible with treatment.

Pigmentation may take weeks to months to return. In rarer cases, especially if left untreated for a long time, tinea versicolor may lead to irreversible hypopigmented spots. In the hyperpigmented type, melanocytes are affected with pigmented granules resulting in brown patches. In the case of the pink variant, there is associated inflammation. The color variation gives rise to the name 'versicolor.' Diagnosis is based on the clinical examination and the microscopic examination of skin scrapings which may demonstrate the fungus.

Treatment is with topical antifungal creams and, in moderate to severe cases, with oral antifungals.

Differential diagnoses include vitiligo, pityriasis alba, pityriasis rosea, postinflammatory hypopigmentation, and idiopathic guttate hypomelanosis.

Diagnosis is usually based on the history of symptoms and clinical examination. Skin scrapings and swabs from the mucosal areas can be examined under the microscope to identify the fungus. The fungus from the affected region can also be grown in artificial culture media. However, it is usually hard to grow fungus in artificial media, and most of the time, they do not yield any growth leading to false-negative results.

Conclusion:

Cutaneous fungal infections are common and indeed embarrassing to many. But a sigh of relief is that these infections are treatable with medications but what is most important is sticking to the longer therapy duration for successful treatment.