Nail Fungus: Symptoms, Types, Causes and Treatment

Nail fungus, medically known as onychomycosis, is far more than a simple cosmetic issue. It can cause discomfort, pain, and even impact your daily activities and self-confidence. Affecting millions worldwide, nail fungus can be stubborn and challenging to eradicate. In this comprehensive guide, we explore the symptoms, types, causes, and the latest evidence-based treatments for nail fungus, helping you better understand this common yet often misunderstood condition.

Symptoms of Nail Fungus

Fungal nail infections can easily fly under the radar in their early stages, but as they progress, the symptoms often become difficult to ignore. Recognizing these signs early can make a significant difference in seeking timely and effective treatment. Let’s break down the most common symptoms and how they manifest.

Symptom	Description	Severity/Impact	Source
Discoloration	Yellow, brown, or white nail color change	Cosmetic + diagnostic	1,2,7
Thickening	Nail becomes thicker than normal	May cause pain, trouble walking	1,2,7
Crumbling	Nail becomes brittle and crumbly	Leads to nail fragmentation	1,2
Onycholysis	Nail separates from nail bed	Crumbly aspect, risk of infection	1,2
Pain	Discomfort or pain in affected nail	Can hinder daily activities	2,10
Nail Shape	Misshapen, distorted nails	Affects function and appearance	2,14
Skin Changes	Scaly, thickened skin around nail	Local irritation	2

Table 1: Key Symptoms

Discoloration and Changes in Nail Texture

• Discoloration is often the most noticeable early symptom. Infected nails may turn yellow, brown, or even white, depending on the type of fungus and the degree of infection. As the infection progresses, the discoloration can become more prominent and spread across the nail plate 1,2,7.
• Thickening is another hallmark sign. The affected nail becomes unusually thick, making it hard to trim and potentially causing discomfort when wearing shoes or walking 1,2,7.
• Crumbling and Brittleness: Over time, the nail may lose its normal strength and become brittle or crumbly at the tips or sides, sometimes breaking off in pieces 1,2.

Nail Separation and Pain

• Onycholysis refers to the partial or complete separation of the nail from the nail bed. This not only gives the nail a crumbly, fragile appearance but also increases susceptibility to further infections 1,2.
• Pain and Discomfort: While many cases are painless initially, some individuals experience pain, especially as the infection advances or if the toenail is involved, sometimes leading to difficulty walking or wearing shoes 2,10.

Changes Beyond the Nail

• Nail Shape and Contour: The infected nail may become distorted, misshapen, or develop an abnormal contour. In severe cases, this can interfere with daily tasks and cause social embarrassment 2,14.
• Skin Involvement: The skin around the affected nail might also show signs of thickening or scaling, particularly in advanced or longstanding infections 2.

Regularly examining your nails and seeking medical attention at the first sign of abnormality can lead to earlier diagnosis and better treatment outcomes.

Types of Nail Fungus

Nail fungus isn't a one-size-fits-all diagnosis. There are several distinct types, categorized by how and where the fungus invades the nail. Each type has unique features and may require a tailored treatment approach.

Type	Main Features	Usual Location	Source
DLSO	Discoloration, thickening	Sides/tip of nail	6,14
WSO	White patches, superficial	Dorsal nail plate	2,6
PSO	Involves nail base/proximal	Nail base	2,6
EO	Internal nail invasion	Within nail plate	6
Candidal Onychomycosis	Thickening, discoloration	Fingernails > toes	6

Table 2: Types of Nail Fungus

Distal Lateral Subungual Onychomycosis (DLSO)

• Most Common Form: DLSO accounts for the majority of fungal nail infections. It begins at the sides or tip (distal/lateral edge) of the nail and spreads toward the cuticle.
• Features: Yellow or white discoloration, thickening, and detachment from the nail bed are typical 6,14.

White Superficial Onychomycosis (WSO)

• Surface Infection: This type affects the uppermost layers of the nail plate, creating chalky white patches.
• Easier to Treat: Because the infection is superficial, topical treatments are often more effective 2,6.

Proximal Subungual Onychomycosis (PSO)

• Uncommon, But Important: PSO starts at the base (proximal end) of the nail, near the cuticle, and is more frequently seen in immunocompromised individuals.
• Red Flag: This form may indicate underlying immune problems 2,6.

Endonyx Onychomycosis (EO)

• Internal Invasion: Here, the fungus invades the inside of the nail plate without causing significant detachment from the nail bed.
• Appearance: Nails may become opaque but usually remain smooth 6.

Candidal Onychomycosis

• Yeast-Driven: Unlike the others, this type is caused by yeasts, especially Candida species.
• Fingernails Most Affected: It often affects fingernails more than toenails and can lead to entire nail detachment in chronic cases 6.

Understanding the specific type of nail fungus is crucial for guiding the best treatment strategy and predicting how the infection might progress.

Causes of Nail Fungus

Nail fungus is caused by a wide variety of fungal organisms, but some types are far more common than others. Several environmental, health, and lifestyle factors can increase your risk of developing onychomycosis.

Cause/Factor	Description	Prevalence/Impact	Source
Dermatophytes	Fungi that digest keratin in nails/skin	Most common (up to 90%)	4,6,14
Yeasts	Candida species, affect fingernails	10-30% of cases	4,14
Non-dermatophyte	Molds, diverse, less common	2-12% of cases	4,5,8
Age	Risk increases with age	Highest ≥40 years	1,11,12
Health	Diabetes, immune suppression, circulation	Increased vulnerability	1,12,6
Environment	Moisture, trauma, occlusive footwear	Major external risk factors	6,8

Table 3: Main Causes and Risk Factors

Fungal Organisms Involved

• Dermatophytes: These are the primary culprits, responsible for up to 90% of toenail and 75% of fingernail fungal infections. Trichophyton rubrum and Trichophyton mentagrophytes are the most frequent offenders 4,6,14.
• Yeasts: Candida species are more likely to infect fingernails, especially in people whose hands are frequently wet or exposed to irritants 4,14.
• Non-Dermatophyte Molds: These include a variety of fungal genera, such as Scopulariopsis, Aspergillus, and Fusarium. They are less common but may be increasing in prevalence, especially in warmer climates 4,5,8,15.

Risk and Predisposing Factors

• Age: The risk of developing nail fungus increases significantly with age. Up to 20% of adults over 40 are affected 1,11,12.
• Health Conditions: People with diabetes, compromised immune systems, poor circulation, obesity, or those who smoke are at higher risk 1,12,6.
• Environmental Factors: Humid environments, frequent exposure to water, trauma to the nail, and wearing occlusive footwear create the perfect setting for fungal growth 6,8.
• Other Factors: Repeated nail trauma, communal showers, and genetic factors may also contribute to susceptibility 6,8.

Understanding what causes nail fungus and recognizing risk factors are key steps in prevention and early intervention.

Treatment of Nail Fungus

Treating nail fungus can be a lengthy and sometimes frustrating process. There is no universal cure, and the best approach depends on the type of fungus, its severity, and individual health factors. Recent advances, however, have improved outcomes for many patients.

Treatment	Mode	Effectiveness	Source
Oral Antifungals	Systemic (pill)	Highest cure rates	3,7,14,15
Topical Agents	Applied to nail	For mild/moderate	6,14,15
Combined	Oral + topical	Increases success	6,7,9
Devices	Laser, phototherapy	Cosmetic, investigational	12,15
Natural Products	Propolis, others	Promising, further study needed	13
Prevention	Hygiene, shoes	Reduces recurrence	7,12,15

Table 4: Treatment Options

Oral Antifungal Medications

• Terbinafine: The current gold standard for dermatophyte infections due to its potency, safety, and minimal drug interactions. A typical course lasts 3-6 months 3,7,14,15.
• Itraconazole and Fluconazole: Broad-spectrum antifungals, effective against dermatophytes and yeasts. Itraconazole is preferred if Candida or non-dermatophyte molds are involved 3,7,14.
• Pros and Cons: Oral medications offer the highest cure rates, but are associated with possible side effects and drug interactions. Liver function monitoring may be required 14,15.

Topical Treatments

• Lacquers and Solutions: Amorolfine, ciclopirox, efinaconazole, and tavaborole are commonly used. Best for mild to moderate cases or when oral therapy is contraindicated 6,14,15.
• Limitations: Lower cure rates compared to oral therapy due to poor nail penetration and the slow growth of nails 14,15.

Combination Therapy

• Synergy: Using oral and topical agents together can increase the chances of complete cure and reduce the risk of recurrence 6,7,9.
• Debridement: Mechanical or chemical removal of diseased nail tissue is often recommended to reduce fungal load and improve medication penetration 7.

Devices and Novel Therapies

• Laser Therapy: Approved for temporary cosmetic improvement; long-term efficacy remains uncertain 12,15.
• Photodynamic and Iontophoresis: Experimental options with some positive early results, but not yet standard of care 12.
• Natural Remedies: Propolis extract has shown promising results in early studies, with over 50% cure rates in some trials, but more research is needed 13.

Prevention and Recurrence

• Hygiene: Keeping feet clean and dry, sanitizing shoes and socks, and avoiding barefoot walking in communal areas are essential preventive measures 7,12,15.
• Prophylactic Topicals: Applying antifungal agents to nails at risk may help reduce recurrence, which remains a common challenge 7,15.

Early diagnosis, a targeted treatment plan, and strict adherence to preventive strategies are vital for a successful outcome and reducing the risk of reinfection.

Conclusion

Nail fungus is much more than a cosmetic concern; it is a common, persistent infection that can significantly impact quality of life. Whether you are dealing with stubborn toenail discoloration or want to minimize your risk, understanding the signs, types, causes, and treatments is the first step toward healthy nails.

Key points from this guide:

• Symptoms: Watch for nail discoloration, thickening, crumbling, separation, pain, and shape changes.
• Types: Several clinical types exist, including DLSO, WSO, PSO, EO, and candidal forms—each with distinct features.
• Causes: Dermatophytes are the most common culprits, but yeasts and non-dermatophyte molds are also involved; risk factors include age, health, and environmental exposures.
• Treatment: Oral antifungals are most effective, but topical and combination therapies are important, especially for mild or moderate cases; prevention is crucial given high recurrence rates.

If you suspect a nail infection, consult a healthcare professional for accurate diagnosis and to discuss the best treatment options for your situation. With the right approach, clear and healthy nails are an achievable goal.