Milk Blister

A milk blister (bleb) is a small white or yellow dot on the nipple tip at the opening of a milk duct, caused by a skin overgrowth covering the pore and trapping milk behind it. It results from a shallow latch, nipple trauma, oversupply, a plugged duct or friction. It occurs in a minority of breastfeeding women, and matters because the pain is sharp and can be severe and the blister can lead to recurrent blocked ducts and mastitis.

• Risk factors: poor latch, nipple trauma, oversupply, blocked duct, tight bra, thrush, previous blister, pump trauma.
• Pain is localised to one spot on the nipple during and after feeds.
• Usually settles by itself within 3 to 7 days; persistent blisters are opened.

Women have a sharp, localised pain on the nipple tip, worse during feeds and relieved when the blister bursts, with a visible white, yellow or clear dot 1 to 3 mm wide on the nipple surface. The breast behind it may be lumpy or tender.

• White dot that does not wipe away.
• Tender area behind the dot (blocked duct).
• Differential diagnosis: blocked milk duct, nipple fissure, nipple candidiasis, bacterial infection, herpes simplex vesicle, impetigo, wart, eczema, galactocele, Montgomery gland, traumatic blister.
• Complications: blocked duct, mastitis, abscess, recurrent blisters, nipple pain, early weaning.

The diagnosis is clinical.

• Inspect the nipple in good light for a white or yellow dot at a duct opening; palpate the breast for a wedge-shaped lump.
• Observe latch and the infant's mouth for tongue tie.
• Swab for bacteria or Candida if there is surrounding redness or pus.
• Temperature and examination for mastitis.

The principle is to soften the blister and clear the duct, with care to avoid infection.

• Supportive: feed frequently with the chin directed to the affected area; warm compress or soak the nipple in warm water with salt (a quarter teaspoon of salt in 120 mL water) for 5 to 10 minutes before feeds, then gently rub with a clean damp cloth to loosen the skin; massage behind the blister toward the nipple during the feed; correct the latch; avoid picking the blister; apply purified lanolin after feeds; wear a loose bra.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); ibuprofen 400 mg oral 8-hourly with food for 3 to 5 days; mupirocin 2 percent ointment applied after feeds 3 times daily for 5 days after unroofing; sunflower lecithin 1200 mg oral 3 to 4 times daily for recurrent blisters; flucloxacillin 500 mg oral 6-hourly for 10 days if mastitis develops, or clindamycin 300 mg oral 6-hourly for 10 days in penicillin allergy.
• Procedures: unroofing of a persistent blister by a trained provider using a sterile 25 gauge needle after warm soaking, lifting the skin without cutting deeply, then expressing the plug by feeding or hand expression.
• Special groups: women with diabetes need careful hygiene and early treatment of infection; breastfeeding continues on the affected side and is compatible with the topical and oral agents used.
• Red flags: fever above 38.5 degrees Celsius, spreading redness, pus, hard lump beyond 48 hours, grouped vesicles, repeated blisters in the same duct, nipple lesion not healing by 3 weeks.
• Follow-up: review in 48 hours; review at 1 week; ultrasound for recurrent blockage; breast examination at 6 weeks.