Fungal Infections: Types, Symptoms, Causes, and Treatments
Fungal skin infections are among the most common and most under-discussed issues in primary care. They show up on the feet, in the groin, on the scalp, in the nails, and in the warm folds of the skin. They are usually not dangerous. But they can be persistent, uncomfortable, and surprisingly hard to fully resolve without addressing more than just the surface.
This article walks through the most common types of fungal infections seen in adults, what causes them, how they are typically treated, and, (or those dealing with recurrent or stubborn infections). what root-cause factors may be worth investigating.
What Causes Fungal Skin Infections?
Most fungal skin infections in adults are caused by a group of fungi called dermatophytes — primarily the genera Trichophyton, Epidermophyton, and Microsporum. These organisms feed on keratin, the protein that makes up skin, hair, and nails.
Dermatophytes thrive in warm, moist environments. They spread through direct skin contact, contact with contaminated surfaces (locker room floors, pool decks, shared towels, gym equipment), and from one body area to another; for example, athlete’s foot can spread to the groin or hands.
Common Types of Fungal Infections in Adults
Athlete’s Foot (Tinea Pedis)
One of the most common fungal infections, athlete’s foot affects the skin between and around the toes and on the soles. It typically presents as itchy, scaly, cracked skin — sometimes with small blisters or a stinging, burning sensation. Walking barefoot in shared damp environments (locker rooms, pool decks, communal showers), wearing tight or non-breathable shoes, and having sweaty feet all increase the risk. Diabetes can both increase susceptibility and make the infection harder to clear.
Most cases respond to over-the-counter or prescription antifungal creams used consistently for several weeks. Keeping the feet clean and thoroughly dry, particularly between the toes after showering or swimming, is essential to both treatment and prevention.
Toenail and Fingernail Fungus (Tinea Unguium / Onychomycosis)
Fungal nail infections cause the nail to thicken, become brittle, and turn white, yellow, brown, or even greenish. The nail may lift away from the nail bed or develop a chalky surface. Toenails are far more commonly affected than fingernails because of the warm, moist environment inside shoes.
Honest expectation-setting matters here: nail fungus is one of the more stubborn infections to treat. Topical antifungals can take many months to show improvement, and oral antifungals, though more effective, require monitoring of liver function and may not be appropriate for everyone. Recurrence is common, particularly when the underlying conditions that allowed the infection are not addressed.
Groin Fungal Infection (Tinea Cruris)
Tinea cruris, sometimes called jock itch, affects the groin, inner thighs, and sometimes the buttocks. It often appears as a red, raised, itchy rash with a clearer center and a defined edge. While historically more often discussed in men, anyone can develop tinea cruris — particularly people who experience profuse sweating, who wear tight or non-breathable clothing, or who already have athlete’s foot that has spread upward.
Topical antifungal creams are the first-line treatment. Loose, breathable clothing, drying the area thoroughly after bathing, and treating any concurrent athlete’s foot are all important to prevent recurrence.
Other Common Fungal Infections
Fungal infections can also affect the body (tinea corporis, often called ringworm — a circular rash with a clearer center), the scalp (tinea capitis, more common in children), the beard area in adult men (tinea barbae), and the skin folds, where yeast (Candida) infections are also common — particularly in warm weather, in people with diabetes, or in skin folds that stay moist.
Who Is at Higher Risk?
Anyone can develop a fungal infection, but the risk is higher for people who have:
- Diabetes, particularly when blood sugar is not well controlled
- A weakened immune system
- Excess moisture in skin folds, between toes, or in clothing
- Frequent exposure to communal damp environments — gyms, pools, locker rooms
- Obesity, which increases skin-on-skin contact and moisture in folds
- A history of recurrent or chronic fungal infections
- Long-term antibiotic use, which can disrupt the body’s normal microbial balance
Integrative Root-Cause Factors — When Fungal Infections Keep Coming Back
From an integrative perspective, recurrent or stubborn fungal infections are not just a topical problem — they are a signal that the body’s internal terrain may be supporting fungal overgrowth. When the same infection keeps coming back despite appropriate topical or oral treatment, it is worth looking deeper.
- Blood sugar dysregulation
- Fungi thrive on sugar. Elevated blood sugar — even at pre-diabetic levels — feeds fungal organisms and impairs the immune response that should be keeping them in check. Recurrent fungal infections can sometimes be the first noticeable sign of glucose dysregulation, and a fasting glucose, hemoglobin A1c, and fasting insulin are reasonable to evaluate.
- Gut dysbiosis and the gut-skin connection
- The gut and the skin share a deep relationship. When the gut microbiome is out of balance — often after long courses of antibiotics, chronic stress, or a high-sugar diet — opportunistic fungal organisms like Candida can overgrow internally, weakening the immune system’s ability to defend the skin. Persistent skin fungal infections paired with bloating, sugar cravings, fatigue, or brain fog are worth investigating from a gut-health angle.
- Immune resilience and nutrient status
- Vitamin D, zinc, and a balanced gut microbiome all support the immune system’s ability to control fungal organisms. Chronic stress, poor sleep, and nutrient deficiencies — particularly common in midlife — can quietly lower immune defenses in ways that show up first as recurrent or stubborn infections.
When to See a Clinician
These situations require evaluation, not just continued over-the-counter treatment. |
How Fungal Infections Are Treated
First-line treatment for most fungal skin infections is topical antifungal medication — terbinafine, clotrimazole, miconazole, or others — applied consistently for the recommended duration, which is often longer than people think (typically 2 to 4 weeks for skin infections, several weeks to months for nails).
Oral antifungal medications may be used for more extensive infections, scalp involvement, or stubborn nail infections. Because some oral antifungals can affect liver function, they are prescribed with appropriate monitoring.
Whether topical or oral, the most common reason fungal infections do not clear is stopping treatment too soon. Visible improvement comes well before the infection is fully resolved. Following the full course matters.
Integrative Support — Alongside Antifungal Treatment
As with any active infection, prescribed antifungal treatment is the standard of care. Integrative support works alongside it — to help the body recover, address the underlying conditions that allowed the infection, and reduce the likelihood of recurrence.
- Reducing dietary sugar and refined carbohydrates
- Because fungi feed on sugar, reducing dietary sugar and refined carbohydrates during and after treatment is a simple, evidence-supported step that can support the body’s ability to clear the infection and reduce recurrence.
- Targeted nutrient and immune support
- Vitamin D, zinc, and a nutrient-dense whole-foods diet support the immune system’s ability to keep fungal organisms in check. When deficiencies are identified, replenishing them during recovery is a useful adjunct to topical or oral treatment.
- Restoring gut balance
- For people with recurrent fungal infections — particularly after antibiotic use — supporting the gut microbiome through a varied whole-foods diet, targeted probiotic support, and reducing factors that disrupt the gut (chronic stress, processed foods, excess sugar) can address the deeper terrain. This is where integrative primary care often does some of its most useful long-term work.
Important: Integrative supports are complementary, not a substitute for prescribed antifungal treatment. Use them alongside the treatment plan from your clinician.
Preventing Fungal Infections
Most fungal infections respond well to good prevention habits:
- Keep skin clean and thoroughly dry — particularly between toes, in skin folds, and after bathing or swimming
- Wear breathable, moisture-wicking fabrics, and change out of damp clothing promptly
- Wear flip-flops or protective footwear in communal showers, locker rooms, and around pools
- Do not share towels, socks, shoes, or personal grooming items
- Treat athlete’s foot promptly to prevent it from spreading to nails or groin
- Manage chronic conditions that increase risk — particularly diabetes
- Address recurrent infections from a root-cause perspective rather than repeated short-term treatments
When to See Your Primary Care Provider
Most fungal infections can be diagnosed clinically and managed in primary care. If yours is recurring, slow to clear, involves the nails, or is happening alongside other symptoms — fatigue, sugar cravings, digestive issues, brain fog — it may be worth more than a topical cream and a wait-and-see approach.
If you do not have a primary care provider — or you have not been able to get in to see yours — Compassion Primary Care is here.
Care That Looks Beyond the Symptom
Compassion Primary Care offers membership-based primary care for adults in the Tampa Bay-Suncoast region — Brandon, Valrico, Riverview, FishHawk, Parrish, Ellenton, Lakewood Ranch, and surrounding areas. Membership means same-week or same-day access for issues like skin and nail infections, longer visits, and an integrative approach that looks for what may be driving recurrent problems.
Three membership options to fit different needs:
- Safe and Sound — foundational primary care membership for everyday health needs
- Gut and Hormone Reset — primary care plus a deeper integrative focus on gut health, hormones, and inflammation
- Prime Health and Optimization — comprehensive care for members investing in long-term wellness
Care is offered virtually, through home visits, and in-person at the Wellness Center of Ellenton.
Learn more or schedule a free discovery call at compassionprimarycare.com.
Clinical References
Information in this article is consistent with current clinical guidance from the following sources. This piece is educational and is not a substitute for an in-person evaluation.
Centers for Disease Control and Prevention (CDC). Fungal Diseases: Information for Healthcare Professionals. cdc.gov
American Academy of Family Physicians (AAFP). Diagnosis and Management of Tinea Infections.
American Academy of Dermatology (AAD). Tinea Infections Clinical Guidance. aad.org
Institute for Functional Medicine (IFM). GI Advanced Practice Module; Immune Advanced Practice Module. ifm.org
American Academy of Anti-Aging Medicine (A4M). Nutritional and Metabolic Medicine. a4m.com
Wessels I, et al. Zinc as a Gatekeeper of Immune Function. Nutrients. 2017;9(12):1286.
Salem I, et al. The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Frontiers in Microbiology. 2018;9:1459.
Disclaimer: This article is intended for educational purposes only and does not constitute medical advice. If you have signs of a fungal infection that is not improving with self-care, please contact a healthcare provider for evaluation. People with diabetes, weakened immune systems, or rapidly worsening symptoms should seek prompt medical attention.
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