Intertrigo (Intertriginous Dermatitis) with Secondary Candidal Infection
In a patient with BMI 37.6 presenting with a rash under the stomach, you should immediately think of intertrigo—a moisture-associated inflammatory skin condition caused by skin-on-skin friction in the abdominal fold—most likely secondarily infected with Candida species.
Primary Diagnosis: Intertrigo
The clinical picture is straightforward: obesity (BMI 37.6) creates the perfect environment for intertrigo in the pannus fold beneath the abdomen 1. This occurs when:
- Skin-on-skin friction combines with trapped moisture from poor air circulation
- The area becomes macerated and inflamed
- The warm, moist environment invites secondary infection
The inguinal region, sub-mammary folds, and abdominal pannus are the most commonly affected sites, with high BMI being a major risk factor 2.
Secondary Infection: Candidiasis
Intertrigo rarely exists in isolation—candidal skin infections typically complicate intertrigo in skin folds, especially in obese and diabetic patients 3. The guideline is clear on this association.
What to Look For Clinically:
- Erythematous, macerated skin in the fold beneath the abdominal pannus
- Satellite lesions (small pustules at the periphery—classic for Candida)
- White, curd-like material or scaling at the edges
- Pruritus and burning sensation
- Possible foul odor if bacterial superinfection present
Diagnostic Approach
While clinical diagnosis is often sufficient, if the presentation is atypical or treatment-resistant:
- KOH preparation showing pseudohyphae and spores confirms Candida 4
- Fungal culture if needed, though treatment can begin empirically 3
- Consider bacterial culture if purulent drainage or worsening despite antifungal therapy
Critical Pitfall to Avoid:
Do not overlook herpes simplex virus in immunocompromised patients—if you see linear erosions or ulcers with a "knife-cut" appearance in the fold, consider HSV and perform direct fluorescent antibody testing 5. However, this is uncommon in otherwise healthy obese patients.
Treatment Algorithm
Step 1: Topical Antifungal Therapy
Use topical azoles (clotrimazole or miconazole) or nystatin for candidal intertrigo 3. These are first-line and highly effective.
Step 2: Keep the Area Dry
This is equally important as medication—moisture control prevents recurrence 3, 1:
- Absorptive powders (not cornstarch, which feeds yeast)
- Barrier creams after the infection clears
- Frequent cleaning and thorough drying
- Consider absorbent cotton material placed in the fold
Step 3: Systemic Therapy if Severe or Extensive
If topical therapy fails or the rash is widespread:
- Oral fluconazole 100-200 mg daily for 7-14 days 3
- Oral itraconazole solution 200 mg daily is equally effective 3
Step 4: Address Underlying Risk Factors
- Screen for diabetes mellitus—strongly associated with inguinal and abdominal intertrigo 2
- Weight management counseling
- Hygiene education
When to Worry: Red Flags
If the patient appears systemically ill with fever, has wooden-hard subcutaneous tissue on palpation, or skin anesthesia, immediately consider necrotizing fasciitis—this requires emergency surgical consultation 6. However, this is rare and presents dramatically different from simple intertrigo.
The key distinguishing feature: In cellulitis or simple intertrigo, subcutaneous tissues are soft and yielding; in necrotizing fasciitis, they feel wooden-hard and you cannot palpate fascial planes 6.
Expected Outcome
With appropriate topical antifungal therapy and moisture control, complete resolution should occur within 2 weeks 4. If not improving, reassess for:
- Non-adherence to keeping area dry
- Resistant Candida species (rare)
- Alternative diagnosis (psoriasis, seborrheic dermatitis, extramammary Paget's disease)
- Bacterial superinfection requiring antibiotics