How should mastitis be evaluated and managed in a non‑pregnant adolescent female?

Mastitis in Never-Pregnant Adolescents

Immediate Clinical Approach

In a never-pregnant adolescent with suspected mastitis, initiate empiric antibiotic therapy targeting Staphylococcus aureus (dicloxacillin 500 mg orally four times daily or cephalexin 500 mg orally four times daily for 7 days) combined with NSAIDs and ice application, after first confirming the diagnosis clinically and excluding inflammatory breast cancer. 1

Diagnostic Evaluation

Clinical Presentation to Confirm

• Focal, unilateral breast pain that is precisely localizable and reproducible by the patient, typically in the subareolar area or nipple region 1
• Inflammatory signs: induration, redness, warmth, and potentially fever 1
• Pain is noncyclical and predominantly inflammatory rather than hormonal in origin 2
• May be associated with duct ectasia with periductal inflammation, particularly in heavy smokers 1

Critical Red Flags Requiring Urgent Evaluation

Before treating as simple mastitis, exclude inflammatory breast cancer if any of the following are present:

• Erythema occupying ≥1/3 of breast surface 1
• Peau d'orange (skin dimpling resembling orange peel) 1
• Bloody nipple discharge 1
• Symptoms in a non-lactating woman that suggest recurrent "mastitis" 1

If red flags are present:

• Perform urgent ultrasound within 24-48 hours to identify abscess or mass 1
• If mass detected: core needle biopsy within 48 hours 1
• If inflammatory breast cancer suspected: punch biopsy of skin, diagnostic mammogram with ultrasound, and multidisciplinary oncology referral within 24-48 hours 1

Imaging Considerations

• Do not perform ductography in patients with active mastitis 3
• Ultrasonography is mandatory if symptoms worsen or recur despite treatment, as approximately 10% of mastitis cases progress to breast abscess requiring drainage 1, 4

First-Line Treatment Algorithm

Initial Conservative Management (First 24-48 Hours)

While antibiotics are typically needed earlier in non-lactational mastitis compared to lactational cases, supportive measures should be initiated immediately:

• NSAIDs for pain and inflammation 1
• Ice application to affected area 1
• Avoid aggressive breast massage or heat application, as these may worsen inflammation 5

Antibiotic Therapy (Initiate Promptly)

Do not delay antibiotic therapy in non-lactating adolescents with clear inflammatory signs, as non-lactational mastitis is more likely infectious from the outset compared to lactational mastitis 1

First-Line Oral Regimens (No Penicillin Allergy)

• Dicloxacillin 500 mg orally four times daily for 7 days (preferred agent targeting methicillin-susceptible S. aureus) 6, 1
• Cephalexin 500 mg orally four times daily for 7 days (equally effective alternative) 6, 1

For Penicillin-Allergic Patients

• Cephalexin 500 mg orally four times daily may be used in non-immediate (non-IgE-mediated) hypersensitivity 6
• Clindamycin 300-450 mg orally three times daily for true penicillin allergy 6

When MRSA Coverage Is Indicated

Consider MRSA-targeted therapy if:

• Local MRSA prevalence is high 6
• Previous MRSA infection 6
• No response to first-line therapy within 48-72 hours 6

MRSA-active regimens:

• Clindamycin 300-450 mg orally three times daily (if isolate is clindamycin-susceptible) 6
• Trimethoprim-sulfamethoxazole (TMP-SMX) 1-2 double-strength tablets orally twice daily PLUS a beta-lactam (TMP-SMX lacks streptococcal coverage) 6

Severe Cases Requiring Hospitalization

Hospitalization is indicated for patients with:

• Fever and chills 3
• Systemic involvement 3
• Concern for sepsis 3

Intravenous regimens:

• Vancomycin 1 g IV every 12 hours (for MRSA or severe infection) 6
• Cefazolin 1 g IV every 8 hours (for penicillin-allergic patients without anaphylaxis risk) 6

Follow-Up and Monitoring

Reassessment Timeline

• Reevaluate within 48-72 hours if symptoms do not improve 6
• If symptoms worsen or persist: perform ultrasound to rule out abscess 6, 1

Abscess Management

If abscess forms (occurs in ~10% of cases):

• Surgical drainage or needle aspiration required 1, 4
• For abscesses <5 cm: needle aspiration/drainage with antibiotic therapy 7
• For abscesses ≥5 cm: no clear evidence favoring surgery vs. aspiration/drainage first 7

Special Considerations in Adolescents

Differential Diagnosis to Consider

Non-lactational mastitis in adolescents may be confused with:

• Mondor disease (thrombophlebitis of thoracoepigastric vein) 2
• Costochondritis (Tietze syndrome) 2
• Chest wall or musculoskeletal pain 2
• Trauma-related pain 2
• Physiologic breast pain at thelarche (breast development) 2

Underlying Pathology

• Non-lactational mastitis may indicate underlying duct ectasia requiring evaluation 1
• In women over 50 years (less relevant for adolescents), evaluation to exclude malignancy is essential 1
• Anaerobes and Staphylococcus aureus are the predominant organisms in acute non-puerperal mastitis 8

Key Clinical Pitfalls to Avoid

• Do not assume all breast pain is mastitis—consider the broad differential diagnosis 1
• Do not delay antibiotics in non-lactating patients with inflammatory signs, as this increases abscess risk 1
• Do not dismiss persistent or recurrent symptoms—these may indicate abscess formation or, rarely, inflammatory breast cancer 1
• Do not perform ductography in active mastitis 3
• Early conservative treatment is crucial to prevent abscess formation and reduce recurrence rates 8