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What is Intertrigo?
Intertrigo is an inflammatory skin condition (dermatitis) that affects the skin folds, including:
- Inguinal (groin) folds
- Axillary (armpit) folds
- Inframammary (under the breasts) folds
- Abdominal folds
- Interdigital (between the fingers and toes) folds
The condition is frequently caused by the proliferation of the yeast Candida albicans, but a wide range of other causes is possible, including bacterial infections, other fungal agents, and various underlying skin diseases.
Intertrigo typically manifests with:
- Redness (erythema) of the affected area
- Skin peeling (desquamation)
- Itching and discomfort in the involved skin folds
The prognosis is generally good, as intertrigo responds well to appropriate and timely treatments. However, if left untreated, complications such as secondary bacterial infections may arise.
Causes and Risk Factors
The causes of intertrigo are numerous and can be broadly classified into:
Purely Inflammatory Conditions
- Allergic contact dermatitis
- Atopic dermatitis
- Irritant contact dermatitis
Infections
- Bacterial infections (e.g., Staphylococcus aureus, Corynebacterium minutissimum)
- Dermatophyte fungal infections
- Yeast infections (primarily Candida albicans)
Associated Skin Diseases
Intertrigo may also be a manifestation of several underlying dermatological conditions that can localize, exclusively or not, to the skin folds, including:
- Seborrheic dermatitis
- Psoriasis (inverse/intertriginous form)
- Hidradenitis suppurativa
- Pemphigus and pemphigoid vegetans
- Darier’s disease
- Familial pemphigus (Hailey-Hailey disease)
Candida albicans: The Most Common Infectious Cause
One of the most frequent causes of intertrigo, especially in the inguinal, inframammary, and abdominal folds, is the overgrowth of Candida albicans. This yeast normally resides in the gastrointestinal tract. Under standard conditions, it does not thrive on skin or mucous membranes. However, specific local conditions can favor its survival and proliferation:
- Increased moisture, such as excessive sweating (hyperhidrosis)
- Use of synthetic fabrics that impair skin breathability
- Elevated glucose in sebum and sweat, which acts as a nutritional substrate for the yeast
For this reason, obesity and diabetes are significant risk factors for developing intertrigo, as both conditions increase local skin moisture and glucose availability.
Age and Seasonal Factors
Intertrigo can affect individuals of all ages, but it is more common in:
- Infants and young children, due to the immaturity of their immune response
- Elderly individuals, due to immune senescence and reduced skin barrier function
Seasonally, summer months represent the peak period for Candida-related intertrigo due to hot and humid weather conditions and increased perspiration.
Transmission
When intertrigo is caused by an infection, its transmissibility depends on the pathogen involved and may occur through direct contact.
However, because the majority of intertrigo cases are due to the proliferation of Candida and other microorganisms that naturally form part of the normal skin microbiome, intertrigo is generally not considered a contagious condition.
An important exception exists: intertrigo is considered highly contagious when it is caused by vegetating syphiloderm lesions, raised, multiple, surface-eroded skin lesions that are an expression of secondary syphilis. In such cases, direct contact with these lesions carries a significant risk of transmission.
Why Are Skin Folds More Prone to Infections?
Skin folds, whether large (such as inguinal folds) or small (such as interdigital spaces), create a unique microenvironment that differs significantly from other skin areas. The continuous contact between the opposing skin surfaces within folds produces physical, chemical, and microbiological characteristics that inherently predispose to inflammation and infection.
Key Features of the Skin Fold Microenvironment
Altered physical-chemical conditions:
- Elevated local temperature
- Increased humidity and moisture retention
- Higher local pH levels
Increased bacterial colonization, including:
- Staphylococcus aureus and Staphylococcus epidermidis
- Micrococci
- Gram-negative bacteria (e.g., Acinetobacter spp.)
Presence and potential overgrowth of yeasts, including:
- Candida albicans
- Malassezia furfur
All these factors combine to make skin folds highly susceptible to both irritant and infectious processes, particularly when systemic predisposing factors (such as diabetes or obesity) are also present.
Symptoms and Clinical Manifestations
Intertrigo typically presents with:
- Patches (flat lesions) or slightly elevated plaques
- Erythema (redness) in the affected skin fold
- Desquamation (skin peeling) and maceration (softening and breakdown of the skin) in the central area of the lesion
This classic presentation, which is often symmetrical, is most commonly associated with Candida infection and inverse (intertriginous) psoriasis, the two most frequent causes of intertrigo.
Variations Based on the Underlying Cause
The appearance of the peripheral border of the lesion provides important diagnostic clues:
-
Pustules (small elevated lesions filled with purulent fluid) suggest:
- Candida infection
- Bacterial infection or superinfection
- Pustular psoriasis
-
Vesicles (small elevated lesions filled with clear fluid) grouped in patches suggest:
- Allergic contact dermatitis
- Atopic dermatitis
-
Vesicles arranged linearly along the periphery of the lesion suggest:
- Dermatophyte fungal infection (e.g., tinea)
-
Uniformly erythematous or buff-colored lesions with well-defined borders and no vesicles or pustules suggest:
- Erythrasma: a bacterial infection caused by Corynebacterium minutissimum
Diagnosis
The diagnosis of intertrigo requires a careful clinical examination, covering not only the skin folds but the entire body surface, as lesions elsewhere may provide valuable diagnostic information.
Clinical Examination
- The presence of erythematous, scaly lesions in areas other than the folds, combined with a family history of psoriasis, may orient the diagnosis toward psoriasis.
- It is worth noting that Candida albicans infections can trigger or worsen inverse psoriasis, so multiple contributing factors may coexist in the same patient.
Wood’s Lamp Examination
- A Wood’s lamp (ultraviolet light) can reveal a characteristic coral-red fluorescence in cases of erythrasma, aiding in its identification.
Mycological Examination
- A mycological (fungal) examination allows confirmation or exclusion of dermatophyte or yeast infections.
- Skin scales are collected and examined under a microscope for direct fungal detection, then cultured on specific growth media.
- Fungal colonies develop within days to weeks, and are identified based on macroscopic and microscopic characteristics.
Biopsy and Immunofluorescence
- When an autoimmune disease (such as pemphigus or pemphigoid) is suspected, a skin biopsy from the lesion site is necessary.
- Direct immunofluorescence is performed to detect autoantibodies and confirm the diagnosis.
Prognosis and Complications
When correctly diagnosed and appropriately treated, intertrigo carries a good prognosis and usually resolves without long-term consequences.
Potential Complications
- Secondary bacterial superinfections are the most common complication, facilitated by:
- Maceration of the skin
- Skin fissures (ragades) that develop in areas of chronic inflammation
- Repeated or chronic intertrigo can significantly impact quality of life, causing pain, discomfort, and social distress, especially in obese individuals or those with diabetes.
Treatment
Treatment of intertrigo is cause-dependent and must be tailored to the specific underlying etiology.
Candida-Related Intertrigo
- Topical antifungal agents (azole derivatives such as miconazole, econazole, ketoconazole) in cream or lotion form are the first-line treatment for localized infections.
- Systemic antifungals (fluconazole, itraconazole) are indicated for extensive or recurrent lesions or in immunocompromised patients.
Inverse (Intertriginous) Psoriasis
- Antifungal therapy may benefit patients with inverse psoriasis, as Candida proliferation is frequently a trigger for this form.
- Topical corticosteroids (cortisone-based creams) can be added for short-term treatment in particularly inflamed (erythematous and desquamating) psoriasis presentations.
- In more severe or refractory cases, dermatologist-guided treatments including calcineurin inhibitors (e.g., tacrolimus) or biologic agents may be considered.
Bacterial Infections or Superinfections
- Antibiotic therapy, either topical or systemic depending on severity, is required when a bacterial infection or superinfection is confirmed or strongly suspected.
- For erythrasma (Corynebacterium minutissimum), topical erythromycin or fusidic acid are commonly used, with oral erythromycin reserved for widespread cases.
Prevention
Preventing intertrigo involves reducing or eliminating the contributing risk factors that create favorable conditions for its development.
Recommended Preventive Measures
- Manage underlying conditions such as diabetes and obesity, as these significantly increase the risk of recurrence.
- Control excessive sweating (hyperhidrosis) through appropriate antiperspirants, breathable clothing, or medical treatment if necessary.
- Avoid synthetic fabrics, opt for natural, breathable materials (cotton, linen) that allow skin transpiration and reduce moisture accumulation in skin folds.
- Avoid occlusive, water-insoluble topical products (e.g., heavy ointments or greasy creams) that worsen maceration in fold areas.
- Avoid alcohol-based solutions on already inflamed skin, as these are poorly tolerated and can exacerbate irritation.
- Keep skin folds dry and clean: gently pat skin folds dry after washing, and consider using absorbent powders (e.g., zinc oxide-based) to reduce moisture in high-risk areas.
- Maintain a healthy body weight: weight loss can significantly reduce the depth and moisture of skin folds, decreasing the risk of intertrigo in overweight or obese individuals.
Sources and Bibliography
- Cainelli T., Giannetti A., Rebora A. Manuale di dermatologia medica e chirurgica. McGraw-Hill, 4th edition.
- Wolff K., Johnson R., Saavedra A. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology, 7th edition. Italian edition edited by Mauro Alaibac. Piccin, 2015.
- Saurat J., Grosshans E., Laugier P., Lachapelle J. Dermatologia e malattie sessualmente trasmesse. Italian edition edited by Girolomoni G. and Giannetti A. 3rd edition, 2006. Masson.
- Janniger CK, Schwartz RA, Szepietowski JC, Reich A. Intertrigo and common secondary skin infections. Am Fam Physician. 2005;72(5):833-838. PMID: 16156342
- Kalra MG, Higgins KE, Kinney BS. Intertrigo and secondary skin infections. Am Fam Physician. 2014;89(7):569-573. PMID: 24695507
