What is the best course of action for a female patient, possibly of childbearing age, experiencing a retracted nipple with pus and pain, potentially indicative of mastitis or an abscess?

Retracted Nipple with Pus and Pain: Urgent Management

This patient requires immediate treatment for a breast abscess with ultrasound-guided aspiration or incision and drainage plus antistaphylococcal antibiotics, as nipple retraction with purulent discharge represents a high-priority condition that demands urgent evaluation to exclude inflammatory breast cancer and prevent progression to chronic infection. 1

Immediate Clinical Assessment

This presentation is concerning and requires urgent workup because:

• Nipple retraction with pus is classified as a suspicious symptom requiring non-deferrable evaluation, as it may represent breast abscess, inflammatory breast cancer, or other serious pathology 1
• The combination of retraction, purulent discharge, and pain distinguishes this from simple mastitis and suggests either an established abscess or potentially malignant process 2
• Breast abscess can mimic inflammatory breast cancer on clinical examination, making timely imaging and tissue diagnosis critical 2

Diagnostic Workup

Imaging Protocol

Ultrasound is the initial imaging modality of choice for evaluating suspected breast abscess:

• Ultrasound should be performed immediately to differentiate between inflammatory mass (phlegmon) and focal abscess collection requiring drainage 3
• If the patient is ≥30 years old, diagnostic mammography should also be obtained to exclude underlying malignancy, particularly given the nipple retraction 1
• For women <30 years, ultrasound alone is typically sufficient unless suspicious findings warrant mammography 1

Critical Differential Diagnosis

The presence of nipple retraction elevates concern for:

• Inflammatory breast cancer - can present identically to breast abscess with pain, erythema, and skin changes 2
• Breast abscess - most commonly develops from untreated mastitis, with Staphylococcus aureus as the predominant organism 4
• Subareolar abscess - particularly in non-lactating women, may be associated with duct ectasia or smoking 5

Treatment Algorithm

If Ultrasound Shows Abscess Collection:

First-line treatment is ultrasound-guided needle aspiration plus antibiotics 4, 3:

• Aspirate pus under ultrasound guidance for both therapeutic drainage and culture 4, 3
• Send aspirate for Gram stain and culture, though treatment should not be delayed awaiting results 4
• Start antistaphylococcal antibiotics immediately: options include cephalexin, dicloxacillin, or clindamycin (if MRSA suspected) 4
• Penicillin, cephalosporins, and erythromycin are considered safe even in lactating women 4

Repeat aspiration in 48-72 hours if symptoms persist 3:

• 19 of 22 abscesses (86%) resolved with aspiration alone in one series 3
• Only proceed to incision and drainage if repeated aspiration fails (typically after 2-3 attempts) 4, 3

If Ultrasound Shows Inflammatory Mass Without Abscess:

• Treat with antibiotics alone targeting S. aureus 3
• Re-evaluate in 48-72 hours - if no improvement, consider biopsy to exclude inflammatory breast cancer 2, 3

If Incision and Drainage Required:

• Can be performed in office under local anesthesia for accessible abscesses 6
• Continue frequent drainage and antibiotics for 7-10 days 6
• This approach has longer healing time and worse cosmetic outcomes compared to aspiration 4

Critical Pitfalls to Avoid

Do not delay imaging and treatment beyond 48 hours, as untreated mastitis/abscess can progress to chronic infection, recurrent mastitis, or sepsis 6:

• Early treatment (within 2 days) prevents serious complications 6
• Breast abscess incidence ranges from 0.4-11% of lactating mothers but can occur in any age group 4

Do not assume this is simple infection without tissue diagnosis if symptoms persist beyond 7 days 2:

• Inflammatory breast cancer can present identically to breast abscess 2
• Any mass or inflammatory changes not resolving with appropriate antibiotics requires core needle biopsy 1

Do not use fine needle aspiration for tissue diagnosis - core needle biopsy is superior for distinguishing benign from malignant pathology and correct histologic grading 1

Follow-up Requirements

• Clinical reassessment within 48-72 hours to confirm improvement 3
• If no improvement or worsening symptoms, proceed to repeat aspiration or surgical drainage 4, 3
• Any persistent mass, skin changes, or nipple retraction after infection resolves requires core biopsy to exclude underlying malignancy 1, 2