Bilateral Inframammary Rash with Yeasty Appearance
This is most likely intertriginous candidiasis (candidal intertrigo), and you should treat it with topical antifungal therapy—specifically topical azoles like clotrimazole, miconazole, or ketoconazole applied twice daily for 7-14 days, combined with measures to reduce moisture and friction in the affected skin folds. 1
Clinical Diagnosis
The bilateral under-breast location and "yeasty" appearance strongly suggest candidal intertrigo, which presents as:
- Erythematous patches with peripheral scaling in opposing skin folds 1
- Satellite lesions (small pustules or papules surrounding the main area of erythema) that are characteristic of Candida infection 1
- Moist, macerated appearance due to friction, moisture accumulation, and lack of ventilation in the inframammary folds 1, 2
Confirm the diagnosis with a potassium hydroxide (KOH) preparation of skin scrapings, which will demonstrate yeasts or pseudohyphae if Candida is present 3, 1. This is particularly important if the clinical presentation is atypical or if initial treatment fails.
Important Caveat: Rule Out Serious Pathology
Before assuming this is simple intertrigo, you must exclude inflammatory breast cancer (IBC) and Paget's disease, especially if there are concerning features 3:
- IBC presents with breast erythema and dermal edema (peau d'orange) involving one-third or more of the breast skin with a palpable border 3
- If the rash is unilateral, extends beyond the inframammary fold onto the breast itself, or is associated with a palpable mass, obtain bilateral diagnostic mammography with or without ultrasound 3
- Antibiotics may be given if infection is suspected, but should not delay diagnostic evaluation if malignancy cannot be excluded 3
Treatment Algorithm
First-Line Topical Antifungal Therapy
Apply topical azole antifungals twice daily for 7-14 days 3, 1, 4:
- Clotrimazole 1% cream 3
- Miconazole 2% cream 3
- Ketoconazole cream 1, 4
- Alternative options: Nystatin, oxiconazole, or econazole 1
Topical azoles are more effective than nystatin and achieve 80-90% cure rates 3.
Adjunctive Moisture Control Measures
Implement these measures simultaneously with antifungal treatment 1, 2:
- Keep the area dry: Pat dry thoroughly after bathing, especially in skin folds 2
- Use absorptive powders like cornstarch (not talc) to reduce moisture 2
- Apply barrier creams to minimize friction 2
- Wear light, nonconstricting, absorbent clothing; avoid synthetic fibers 2
- Place cotton or gauze between skin folds to absorb moisture and reduce friction 1, 2
For Resistant or Severe Cases
If topical therapy fails after 7-14 days, prescribe oral fluconazole 3, 1:
- Oral fluconazole is the drug of choice for refractory candidal infections 3
- Typical dosing for mucocutaneous candidiasis: 100-200 mg daily for 7-14 days 3
Secondary Bacterial Infection
If bacterial superinfection is suspected (increased pain, purulent drainage, honey-colored crusting), consider 1, 2:
- Bacterial culture or Wood lamp examination to identify the pathogen 1
- Group A beta-hemolytic streptococcus: Treat with topical mupirocin or oral penicillin 1
- Corynebacterium minutissimum (erythrasma): Treat with oral erythromycin; shows coral-red fluorescence under Wood lamp 1
Common Pitfalls to Avoid
- Do not assume all inframammary rashes are benign intertrigo—always consider and exclude IBC or Paget's disease if there are atypical features 3
- Do not treat Candida colonization in asymptomatic patients—approximately 10-20% of women harbor Candida without symptoms 3
- Do not rely solely on clinical appearance—obtain KOH preparation if diagnosis is uncertain or treatment fails 1
- Do not neglect moisture control measures—antifungal therapy alone without addressing the underlying moisture and friction will lead to recurrence 1, 2
- Do not use topical corticosteroids alone—these can worsen fungal infections, though they may be combined with antifungals in severely inflamed cases under close supervision 1