Introduction

Tinea manuum is a fungal skin infection that affects the hands and palms. It can be caused by many different types of fungi and can affect people anywhere in the world. However, it's sometimes tricky to figure out if you have tinea manuum, but quick and correct diagnosis is key to effective treatment. 

This article explores the factors that make someone more likely to get this infection, explains the right way to diagnose and treat it, and emphasises how a team of healthcare professionals can provide the best care, especially when the diagnosis is uncertain or the condition keeps coming back.

Definition of tinea manuum

Tinea Manuum is not as common as foot fungus (tinea pedis, otherwise known as athlete’s foot), but it can still be a significant problem.

You can acquire tinea manuum in several ways, including:

• Making physical contact with another area of your body with a fungal infection, like the feet (tinea pedis) or groin (tinea cruris)
• Contact with someone else who has a fungal skin infection
• Direct contact with infected animals or soil
• Contact with contaminated objects, like towels or gardening tools

This infection is more likely to occur in people who do manual labour, sweat a lot (hyperhidrosis), or already have dermatitis on their hands.¹

Causes and risk factors of tinea manuum

Dermatophyte infections (skin infections caused by fungi) are widespread and affect a significant portion of the world's population - thought to be between 10% and 25%. Among these infections, tinea pedis (foot fungus) and tinea manuum (hand fungus) are the most common. Tinea pedis, in particular, affects up to 70% of adults. Adolescents and adults assigned male at birth are more frequently affected.²

What's intriguing is that even if people have similar risk factors for getting these fungal infections, not everyone gets them. This tells us that the interaction between the person, fungus, and environment is pretty complex. In fact, some recently published research shows that some people have certain genetic factors that make them more prone to severe, invasive fungal diseases. These genetic factors affect their immune system's ability to fight off these infections.

Fungal infection

Tinea manuum is the result of a fungal infection, and the most common culprit globally is a fungus called Trichophyton rubrum. Other types of fungi can also be responsible for this condition in different parts of the world. Generally, however, the fungi causing tinea manuum thrive in warm and humid environments. You can often find them in tropical regions. They particularly like to grow in damp places like locker rooms and public showers.

Tinea manuum is highly contagious. You can catch it from various sources, including:³

• Coming into contact with people who have it
• Touching animals or soil that are infected with fungi
• Using items or touching surfaces that carry the fungus

It’s important to note is that the fungi responsible for tinea manuum can survive for a long time on objects and surfaces, which makes it easy to contract the infection.

Interestingly, many people develop athlete's foot (tinea pedis) before experiencing tinea manuum. This is because the fungus is so good at spreading, and you can transfer it from your feet to your hands simply by scratching your feet. Therefore, it's crucial to be aware of the risk factors that increase your risk of fungal skin infections and to know how to manage them effectively.⁴

Risk factors for contracting tinea manuum

Several factors and conditions can increase your risk of getting tinea infections and onychomycosis (fungal nail infections). These include:^5,6

• Biological sex: individuals assigned male at birth are more prone to fungal skin infections
• Medical history: certain health conditions can make you more susceptible to fungal skin infections, including:
  • Diabetes
  • Hypertension (also known as high blood pressure)
  • Atherosclerosis
• Spending a lot of time in humid environments: high humidity levels are favourable for these fungal infections. Factors like excessive sweating (hyperhidrosis), foot moisture (maceration), and the prolonged use of closed shoes all increase your risk of tinea infections. Additionally, places like communal baths and public sports facilities can be breeding grounds for these fungi
• Scratching infected skin: scratching the soles of your feet or picking at toes infected with tinea can introduce the fungus to your hands
• Occupation and hobbies: certain occupations and activities can increase the risk. For example, farmworkers and people who own pets like guinea pigs and hedgehogs might be at higher risk. Also, individuals with jobs that involve recurrent hand trauma or exposure to chemicals, such as car mechanics and machine operators, are more prone to these infections

Spread of infection

Tinea manuum is incredibly contagious. It primarily spreads in three ways:

• Through people: you can contract tinea manuum by coming into direct contact with someone who has the infection, regardless of whether or not they show symptoms. Even if they don't have obvious signs, they can still pass it on
• Through animals: touching animals with a fungal infection can transmit tinea manuum. Many different animals can carry it, including pets like dogs and cats, especially puppies and kittens. Even farm animals like cows, horses, pigs, and goats can spread it
• Through fomites: fomites are objects or materials that can carry infections. Indirect contact with fomites can give you tinea manuum. This can happen when you share items like clothes, towels, and bedding with someone who has the infection. The fungus can also live on hard surfaces, especially in humid places like locker rooms and public showers⁷

In addition to these mediums of infection, tinea fungi can be found in the environment (such as in the soil). It can even move from one part of your body to another. 

Symptoms of tinea manuum

Tinea manuum can cause various symptoms depending on the type of fungus causing it. However, these symptoms may include:⁸

• Ringworm-like rash: sometimes, tinea manuum presents as an acute, inflammatory rash, similar to the rash caused by ringworm (tinea corporis). This rash often has a raised border with a clearing in the middle. This rash is more likely when the responsible fungus comes from animals or the environment
• Hyperkeratotic tinea: more frequently, tinea manuum causes peeling, dryness, and mild itching on one palm, which slowly spreads over the hand. This can result in increased skin markings. Usually, both feet appear similar, giving rise to what's known as the "one-hand, two-foot syndrome." The primary cause of this form is a fungus that primarily infects humans
• Blistering rash: some fungi may cause a blistering rash to appear on the edges of the fingers or palm. The blisters often appear in groups and contain a sticky clear fluid. They may have peeling edges and cause itching and burning
• Some patients may complain of thickened skin or itching (pruritus)

Diagnosis of tinea manuum

Taking a medical history and physical examination 

Tinea Manuum can manifest in different ways, and its symptoms can vary between patients and cases. You may be asymptomatic (not experience any symptoms at all), or experience one or more of the symptoms described above. 

Typically, the infection is unilateral and only affects one hand. The back of the hand can exhibit a similar appearance to tinea corporis - which is characterised by a red plaque surrounding by an active border with vesicles (small blisters) and scales. This rash tends to grow outward.⁹

The most common clinical presentation is what's called the "two-foot, one-hand syndrome." In this scenario, both feet are affected, and one hand shows scaly patches or moderate to severe dryness. In some patients, Tinea Manuum and onychomycosis (fungal nail infection) can be present in the same hand or even in both hands.¹⁰

Laboratory tests

Once a healthcare provider suspects you have tinea manuum based on your medical history and clinical examination, it's crucial to obtain mycological confirmation by using tests specific for fungi, such as:^11,12,13

Direct microscopy

This is a simple and quick way to detect fungal hyphae (filaments). A swab or scraping from the affected area is treated with potassium hydroxide and examined under a microscope, and results are typically available within 24 hours. However, potassium hydroxide smears have limitations, so they are often complemented with culture (growing up the causative fungus to identify it). Cultures can take 2 to 6 weeks to grow, so treatment should not be delayed while waiting for results. Antifungal susceptibility testing can be added to the culture to determine the fungus's susceptibility to specific antifungal medications.

Fluorescent staining

This method can increase the detection rate of fungi. It uses a stain that selectively binds to chitin (a substance found in fungal cell walls) causing it to fluoresce with an apple-green colour when viewed under a fluorescent microscope.

Histopathology

In some cases, such as when other skin diseases are considered in the differential diagnosis, a histopathological examination (i.e. the examination of cells and tissues under a microscope) may be necessary to confirm a diagnosis.

Dermoscopy

This non-invasive tool examines the skin using surface microscopy and has been recently described as useful in diagnosing tinea manuum.

Advanced molecular methods

In larger institutions and for research purposes, more advanced techniques like PCR, real-time PCR, and newer molecular methods are used for dermatophyte differentiation.

Differential diagnosis of tinea manuum

Several other skin conditions can present with symptoms similar to tinea manuum, making it essential to differentiate between them. Here are some conditions that present similarly to tinea manuum and therefore are part of the differential diagnosis:^14,15

• Psoriasis: psoriasis typically appears on both sides of the body and causes and hyperkeratotic (thickened) lesions on the palms and soles. Psoriasis may also cause vesicular lesions, nail pitting, and the "oil drop sign" - a circular area of discoloured skin under the nail of the right pinky finger
• Dyshidrotic eczema: this condition is characterised by the appearance of itchy vesicles on the fingers, toes, palms, and soles. It may be related to stress or seasonal allergies
• Contact dermatitis: contact dermatitis can be irritant or allergic. It causes erythematous (red) and pruritic (itchy) skin lesions to appear on the palms and backs of the hands. It often appears bilaterally. Patients may find that the skin lesions occur after contact with a foreign substance, like poison ivy or nickel
• Inflammatory bullous dermatophyte infections: these fungal infections can sometimes be misdiagnosed as herpetic whitlow (caused by herpes simplex infection), bacterial bullous impetigo, or cellulitis

Treatment of tinea manuum

There are various treatment options for tinea manuum, both topical and oral, but the treatment your doctor chooses for you will depend on the extent of your infection, your medical history, and your lifestyle. Treatment options include:^16.17,18

• Topical therapy: topical antifungal treatments are generally preferred for tinea manuum because they carry a lower risk of drug interactions and side effects compared to oral treatments
• Antifungals: treatment success rates are similar among different types of antifungal medications, including allylamines (such as terbinafine and naftifine), imidazoles (such as clotrimazole, fluconazole, itraconazole, and ketoconazole), and other antifungals like butenafine and ciclopirox olamine. Treatment regimens typically last 4 to 6 weeks. Some newer options like luliconazole and econazole may require shorter treatment periods, usually about 2 to 4 weeks

If your infection involves the nails or a large area of the body, oral antifungal medication may be recommended. This is particularly important if you have a weakened immune system, topical antifungals are ineffective, or you experience recurrent infections. Oral medications may include terbinafine (Lamisil®) and itraconazole (ONMEL®).

• Corticosteroids: the use of corticosteroids to treat fungal infections is somewhat controversial, but they can help reduce itching or burning caused by inflammation. In some patients, corticosteroids are used alongside antifungal therapy, but they are generally limited to the first week of antifungal treatment to avoid potential side effects

Treatment decisions should be made in consultation with a healthcare provider.

Preventing tinea manuum

Preventing tinea manuum is essential, and there are several steps you can take to reduce your risk of infection:¹⁸

• Practice good hygiene: regularly wash your hands with soap and water, and make sure to dry them thoroughly. Keep your fingernails short and clean to prevent fungal growth
• Avoid scratching your feet: touching or scratching your feet, especially if you have an athlete's foot (tinea pedis), can increase your risk of transferring the fungal infection to your hands
• Treat infections promptly: if you have a fungal infection, it's crucial to treat it quickly and completely. This helps prevent the spread of the infection to other parts of your body, including your hands
• Avoid topical steroid creams: while corticosteroid creams may temporarily relieve itching, they won't treat the fungal infection and can delay the correct diagnosis. Avoid using them without medical guidance
• Don't share personal items: avoid sharing clothing, towels, bedding, or other personal items that may harbour fungi
• Be careful around animals: if you come into contact with pets or other animals, wash your hands afterwards. If you suspect your pet has a fungal infection, you should consult a veterinarian.
• Athlete precautions: if you're involved in contact sports, make it a habit to shower immediately after practices, matches, and games. Do not share sports equipment, and ensure that your uniform and gear remain clean

By following these preventive measures, you can significantly reduce the risk of contracting tinea manuum and related fungal infections.

Complications of tinea manuum

Delays in diagnosing and/or treating tinea manuum can lead to various complications, such as:¹⁹

• Secondary infections: in cases of inflammatory tinea manuum, particularly those contracted from animals, secondary bacterial infections can occur
• Lymphangitis: this refers to the inflammation of the lymphatic vessels. It has been described in cases of inflammatory tinea manuum, most commly when the infection has been acquired from an animal
• Contact dermatitis: topical imidazole antimycotic therapy, although generally safe, can rarely lead to contact dermatitis as a complication of its use. This is a skin reaction to the antifungal treatment
• Disuse contractures: in some cases, patients with tinea manuum and concurrent irritant contact dermatitis have reported disuse contractures of the flexor tendons. This can limit your hand movement and function

The key to avoiding these complications is diagnosing and treating tinea manuum early. 

Summary

• Tinea manuum is a contagious fungal infection of the hands which can caused by various fungi
• Tinea manuum can be contracted via contact with infected people or animals, or contaminated objects in warm, humid environments
• Biological sex, previous health conditions, humid settings, and occupations can increase an individual’s risk of tinea manuum
• The symptoms of tinea manuum can vary, but can include a ringworm-like rash with raised borders to peeling and dryness, blistering, itching, and burning
• Diagnosis of tinea manuum involves a medical history, physical examination, and laboratory tests, including direct microscopy and cultures
• Treatment options include topical and oral antifungal medications. Corticosteroids may be used in conjunction with antifungals. The choice of treatment depends on the extent and severity of the infection
• Delayed diagnosis can lead to bacterial infections, lymphangitis, and skin reactions. As such, early intervention is vital