Table 2 Unnecessary and poorly defined diagnoses in Clinical Protocol #36 may increase the risk of antibiotic overtreatment

“Inflammatory mastitis presents as an increasingly erythematous, edematous, and painful region of the breast with systemic signs and symptoms such as fever, chills, and tachycardia” [1, p. 363]

Mastitis means ‘inflammation of the breast’.

• Because all mastitis is inflammatory, the tautology ‘inflammatory mastitis’ is not a useful term or diagnosis.

• More severe presentations on the spectrum of mastitis are associated with systemic signs and symptoms [5], not necessarily because of bacterial overgrowth [44].

“Bacterial mastitis represents a progression from ductal narrowing and inflammatory mastitis to an entity necessitating antibiotics or probiotics to resolve … Bacterial mastitis presents as cellulitis (worsening erythema and induration) in a specific region of the breast that may spread to different quadrants … An evaluation by a medical professional should be performed if there are persistent systemic symptoms (> 24 hours) such as fever and tachycardia. In the absence of systemic signs and symptoms, diagnosis should be considered if the breast is not responding to conservative measures” [1, p. 363]

“e. Reserve antibiotics for bacterial mastitis” [1, p. 370]

Signs and symptoms which indicate a progression from ‘inflammatory mastitis’ to ‘bacterial mastitis’ are not able to be defined.

• Recommendation for a medical professional assessment after 24 h of systemic signs implies that after 24 h ‘inflammatory mastitis’ may have become ‘bacterial mastitis’, requiring treatment with antibiotics or probiotics (see Table 1 for discussion re probiotic efficacy).

• Human milk and breast stromal bacteria interact with and are altered by all presentations of breast inflammation [4].

• Cellulitis is a bacterial skin infection; mastitis is an inflammatory condition of the breast stroma, associated with secondary inflammatory changes in the skin.

• Fevers are not linked to abscess formation; even with fever, most breast inflammations resolve with conservative measures, including fit and hold intervention and increased frequency of feeds [5] [60].

• Persistent signs and symptoms at the most severe end of the spectrum of breast inflammation over the passage of multiple days may require antibiotics.

“Phlegmon should be suspected with a history of mastitis that worsens into a firm, mass-like area without fluctuance. … Acute bacterial mastitis … can progress to phlegmon. Lactational phlegmon may require extended antibiotics for complete resolution, but cases should be considered individually” [1, p. 373].

This use of the term phlegmon risks unnecessary imaging and antibiotic use [5].

• Term ‘phlegmon’ is poorly defined and used inconsistently in medical practice [61], referring variously to a localised area of soft connective tissue inflammation; an inflammatory mass; diffuse, spreading inflammation; or cellulitis [62].

• An abscess is a collection of pus walled-off by granulation tissue, distinct from phlegmon.

• Lactational phlegmon cannot be diagnosed by a specific set of presenting signs and symptoms. It can’t be both a tender, erythematous and non-fluctuant mass on the spectrum of breast inflammation presentations, and yet also a distinct clinical entity [1, 63]. Radiologists diagnose phlegmon by subjective criteria when imaging a lactation-related lump to exclude abscess.

• Although the finding of a phlegmon on imaging indicates greater inflammatory severity due to discernible amounts of interstitial fluid, there is no rationale for the assertion that phlegmonmay be bacterial, requiring an extended course of antibiotics [63].

• Close clinical monitoring is required. No follow up imaging necessary if presenting signs and symptoms resolving [5].

• Antibiotic use indicated if signs and symptoms of breast inflammation worsening as multiple days pass rather than resolving, or because imaging has identified an abscess [5].

“Subacute mastitis occurs when ductal lumens become narrowed by bacterial biofilms in the setting of chronic mammary dysbiosis” [1, p. 365]

This use of the term subacute mastitis with its associations of biofilm and mammary dysbiosis increases risk of unnecessary antibiotic use.

• Subacute mastitis unable to be defined by presenting signs and symptoms.

• See elsewhere for analysis of studies which claim to define subacute mastitis [5].

“A galactocele develops when ductal narrowing obstructs the flow of milk to the extent that a significant volume of obstructed milk collects in a cyst-like cavity” [1, p. 365]

“Galactoceles, which can result from unresolved hyperlactation, can become infected” [1, p. 360]

“An infected galactocele requires drainage as well as antibiotics” [1, p. 373]

This pathophysiological theory of galactocoele development doesn’t consider alveolar rupture, associated apoptosis, and resultant tissue destruction which occur in subclinical inflammatory development of galactocoeles [5].

• Pathophysiological mechanism by which galactocoeles are hypothesised to result from ‘hyperlactation’ not described.

• Term ‘infected galactocoele’ is redundant because galactocoele which becomes infected has become an abscess.