Differential Diagnosis for Erythema Under the Breast

• Single Most Likely Diagnosis
  • Intertrigo: This is the most likely diagnosis due to the location under the breast, which is a warm, moist area prone to skin friction and fungal or bacterial overgrowth. Intertrigo is a type of skin inflammation caused by skin friction and moisture, making it common in areas like under the breast.
• Other Likely Diagnoses
  • Candidiasis: Given the warm and moist environment under the breast, candidiasis (a fungal infection) is a plausible cause. It often presents with redness, itching, and sometimes a white discharge.
  • Contact Dermatitis: This could be due to an allergic reaction or irritant from clothing, soaps, or other products coming into contact with the skin under the breast.
  • Eczema (Atopic Dermatitis): While less common in this specific location, eczema can occur anywhere on the body and might be considered, especially if the patient has a history of atopic diseases.
• Do Not Miss Diagnoses
  • Inflammatory Breast Cancer: Although rare, this aggressive form of breast cancer can present with skin changes such as redness and swelling, making it crucial not to miss. Any persistent or unusual skin changes under the breast should prompt further investigation.
  • Cellulitis: A bacterial infection of the skin that can spread quickly and become serious. It requires prompt antibiotic treatment.
• Rare Diagnoses
  • Granuloma Gluteale Infantum: Though more common in the diaper area of infants, it can occasionally occur in other intertriginous areas, including under the breast, especially in the context of prolonged moisture and irritation.
  • Langerhans Cell Histiocytosis: A rare disorder that can cause skin lesions, among other symptoms, and might be considered in the differential for unexplained or persistent skin changes under the breast, especially in children.