Intertrigo

Etiology

Mechanical factors and secondary infections are vital contributors to intertrigo. Heat and maceration have central roles in facilitating this process. The skin folds experience constant friction, leading to irritation and, at times, erosion of the inflamed skin. Additionally, moisture accumulates in the affected intertriginous areas, creating an environment conducive to secondary infections. Candida species thrive in warm, high-moisture conditions, making them a common cause of secondary infections in intertrigo cases.

Furthermore, patients with diabetes often have elevated pH levels in intertriginous areas, which contributes to their higher prevalence of intertrigo.[4] Also, gram-positive and gram-negative bacteria and other fungi and viruses are common causes of secondary infections in some cases.[5][6][7]

Epidemiology

Intertrigo can affect individuals of all ages, from infancy to advanced age. The inflammatory condition often presents as a variation of diaper dermatitis in infants. Furthermore, factors such as a naïve or weakened immune system, limited mobility, and urinary or fecal incontinence contribute to the skin manifestations and their complications.[3] Obesity and diabetes are conditions that increase the likelihood of developing intertrigo.[6] The condition is most prevalent in geographic areas with hot and humid climates. Additionally, no ethnic or gender predilection has been observed.

Pathophysiology

Environmental and genetic factors play a significant role in the development of intertrigo. Friction between adjacent skin surfaces is a key factor leading to epidermal inflammation. Flexural areas also tend to have higher surface temperatures than other body parts, which, when combined with moisture and sweat build-up, contribute to the maceration of the stratum corneum and epidermis. Moreover, the integumentary system contains bacteria and yeast that thrive in this environment and can overgrow under these conditions, making infections a common occurrence.[5][6][7]

Histopathology

No characteristic histological changes are typically seen in intertrigo, although some cases may show mild spongiosis in the epidermis.

History and Physical

Intertrigo typically presents with a chronic, subtle onset of pruritus, burning, tingling, and pain in skin folds and flexural surfaces. An acute change in symptoms may indicate a secondary infection with Candida albicans, bacteria, or other pathogens. The patient is often engaged in activities that result in skin surfaces rubbing together. Hot and humid environmental conditions further aggravate the condition, contributing to its pathology. As a result, intertrigo tends to have a higher incidence during certain seasons.

Hyperhidrosis, often triggered by strenuous exercise, significantly contributes to this inflammatory condition. Predisposing factors such as obesity, diabetes, incontinence, urethral discharge, and draining wounds all create a warm, moist, and occluded environment that promotes the development of intertrigo.[8]

Intertrigo is most prevalent among patients with obesity, though it can affect individuals of any body mass index (BMI) depending on other factors. The increased surface area in patients with obesity accentuates the folds and creases of the body, creating an environment conducive to higher temperatures.

The initial presentation noted during a skin examination typically reveals a mildly erythematous patch on both sides of the skin fold. The degree of inflammation varies based on location, duration, and the presence of secondary infection. Over time, the erythematous patches may develop erosions, maceration, fissures, crusting, and weeping.

If pustules, crusts, or vesicles are visible, secondary infection should be considered. Satellite papules and pustules are pathognomonic if Candida spp are suspected. A bluish-green tint may indicate infection with Pseudomonas.[9] Bacterial intertrigo often presents with weeping, intense erythema, and tenderness.[5] In cases of interdigital intertrigo, Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum are commonly implicated organisms.[10]

Evaluation

Further evaluation beyond clinical diagnosis may be needed to determine the exact cause and most effective treatment. If a bacterial infection is suspected, the lesion can be cultured. For fungal infections, a skin scraping from the active margin of the lesion should be taken, and a 20% potassium hydroxide (KOH) solution should be added to aid detection. Under light microscopy, the presence of hyphae or budding yeast confirms a fungal infection. If the presentation is atypical or treatment has failed, a biopsy should be considered for further investigation.

A Wood lamp can aid in detecting infections caused by Pseudomonas or erythrasma (Corynebacterium minutissimum).[11] In cases of difficult-to-treat or recurrent episodes, fasting blood glucose levels should be obtained to evaluate for potential underlying diabetes.

Treatment / Management

Intertrigo can be effectively treated by identifying and addressing the underlying cause of the condition. As mentioned above, the offending factor or agent should be minimized or eliminated. If the rash is due to an infection, appropriate antimicrobial therapy should be initiated. In cases of simple intertrigo, drying agents such as antiperspirants can help reduce moisture. After physical activity that leads to excessive perspiration, bathing or showering, followed by gentle drying with a soft towel, is recommended.[12]

Triple paste, which contains aluminum acetate solution, zinc oxide, and petrolatum, is an effective antiperspirant that reduces friction and alleviates skin irritation. Staying cool by wearing loose clothing and working in air-conditioned environments can help prevent the rash. Other effective preventative measures include using absorbent powders combined with a 1:40 aqueous solution of aluminum triacetate and applying wet tea bags. While absorbent diapers are particularly effective at reducing moisture, petrolatum ointment or cream is also a safe and effective option for treating diaper dermatitis if needed.

Topical treatments such as mupirocin or bacitracin may be effective for lesions infected with mild bacteria. Flucloxacillin or erythromycin, which targets gram-positive bacteria such as Staphylococcus or Streptococcus, should be prescribed if oral medication is necessary. For yeast or fungal infections associated with intertrigo, topical options such as clotrimazole, ketoconazole, and oxiconazole are effective. Topical nystatin is specifically effective for candidal intertrigo.

Topical treatments should be applied twice daily until the rash resolves. For resistant fungal infections, oral fluconazole at a dosage of 100 to 200 mg daily for 7 days may be effective.[13] Low-dose steroids, such as hydrocortisone cream, can be considered for their anti-inflammatory properties, although they are not always necessary. A lower-strength steroid is preferred to prevent atrophy in the already thinner epidermis of the flexural surfaces.[14][15](A1)

Differential Diagnosis

The differential diagnosis for intertrigo is extensive, as many other conditions can occur in the flexural surfaces. However, it is crucial to rule out infections and identify the specific infectious agent to provide the appropriate antimicrobial therapy needed to eliminate the offending organism. Bacteria, viruses, dermatophytes, and Candida species can all cause intertrigo or provoke a secondary infection.[16] Once an infection has been ruled out, further investigation of other similarly presenting conditions commonly found in the flexural areas can proceed.

More common conditions, such as seborrheic dermatitis, irritant or allergic contact dermatitis, atopic dermatitis, inverse psoriasis, pemphigus, scabies, metabolic derangements, and malignancies, frequently present in skin folds and can mimic intertrigo.[17] Nonetheless, intertrigo remains primarily a clinical diagnosis characterized by the findings and clinical picture previously described.

Prognosis

The prognosis is positive for most patients, especially when underlying risk factors are addressed to reduce intertrigo outbreaks. However, if risks such as diabetes and obesity are not effectively managed, the condition is likely to relapse frequently.

Complications

The primary complications associated with intertrigo are secondary infections, as discussed previously. Patients should seek clinical guidance to properly manage rashes to optimize infection prevention. If left untreated, the rash may progress to cellulitis.[18]

Furthermore, sepsis can arise from hidden ulcers that develop in unsupervised patients or individuals with obesity. Contact dermatitis may be a secondary reaction to topical agents used to treat the rash. Prolonged steroid use can lead to atrophy and striae in the thinned epidermis of the flexural surfaces.