How nipple wounds heal

There is no international consensus on wound care in general

There is currently no international consensus on optimal wound care even after common skin procedures and excision, with patients receiving a wide variety of recommendations. So it’s not surprising, given that the clinical support of breastfeeding remains a research frontier, that there is actually very little research into how best to heal nipple wounds.

You will notice, however, that people will tell you to keep the wound moist and covered with various tailor-made nipple wound products as if this is the safest, most effective and evidence-based way. This advice is strongly promoted by a range of nipple wound care coorporations, but is not evidence-based.

It usually takes seven to ten days to heal damaged epidermis, but our nipples are highly vascular and heal quicker than other parts of the skin. A normal layer of epidermis will recover from damage in around three days, though the skin will still be fragile. So cracks and ulcers, depending on their depth, can heal fast – if they are not exposed to repeated micro-trauma and environmental humidity.

Once stretching forces have caused the nipple skin to break, a well-ordered process of wound healing begins.

Step 1. Clotting (haemeostasis)

There will be some bleeding, even if microscopic. Blood from damaged nipples may even on occasions result in the baby vomiting swallowed blood, and if this is clearly related to nipple damage, you can be reassured it won’t hurt the baby. Often, the bleeding from a small break or crack is not something mothers notice.

Once the skin is broken, a cascade of signalling pathways in the inflammatory pathway result in increased fluid leaking from the blood vessels, as wound exudate. Platelets are carried by the blood stream to the site of damage and stick together like glue, forming a clot to stop bleeding. This is known as ‘homeostasis’. The clot contains blood cells and fibrin and prevents more blood and fluids from flowing out.

Step 2. Inflammation

As well as platelets, a cascade of signals from the broken epidermis triggers an inflammatory process. Messenger signals call in white immune cells. Inflammation results in proliferation of immune cells and deposition of extracellular matrix.

When wounded, fluid inflow from the blood vessels increases due to vascular leakiness triggered by inflammation and this is observed on the wound surface as exudate. This acute wound fluid is cloudy or milky, perhaps thin and watery, and contains fibrin. It is a transport vehicle for bioactive molecules. It supports the proliferation of fibroblasts and keratinocytes rich in leucocytes and nutrients. Wound exudate is a leakage of healing moisture, an opaque soup of bioactive molecules, a protective mix of growth factors, cytokines, electrolytes, proteases, white cells, enzymes, growth factors, and hormones, and proteins such as fibrinogen and fibrin.

The different cells in the wound area communicate with each by the medium of the exudate, ensuring coordinated healing and combating infection. The wound exudate is an essential part of wound healing because it provides an appropriately moist environment.

A purulent exudate, with bacterial overgrowth, is milky, thicker, gray green or yellow, with an unpleasant smell.

Inflammation and the microbiome

A wound creates an area filled with moisture, warmth and nutrients, where the balance of the microbiome is disturbed. This creates opportunities for colonisation by new microorganisms or for expansion by existing microorganisms. To heal a wound, the wound needs a balance of a diverse population of bacteria and fungi dynamically co-existing but controlled by the immune system.

As the clot hardens and dries out, a scab forms. You can find out about the scab and its role here.

The eschar or scab is usually crusty and may be yellowish, orange, or brown. Scab is dehydrated, dead cells in a fibrin mesh, which seals the breach in the epidermis and acts as a carapace. Blisters are like bubble wrap protecting the wound. Both keep micro-organisms out and allow the skin cells and broken blood vessels underneath to heal.

Patients are best not to try to break a blister themselves, or to remove a scab. Direct breastfeeding or pumping tends to remove them both, but at the same time exposes the underlying skin to healing fluids. If a mother is worried about the extent of the scab, and that it may be too large for the baby to easily swallow, then her nipple needs a break from breastfeeding, to heal. We don’t want to take off the crust unless its removed naturally by the moisture of pumping or direct breastfeeding, in order to protect the fragile new cells underneath.

Step 3. Proliferation

The synthesis of collagen generates a new tissue matrix where granulation tissue is laid down. The stimulation of new blood vessels into the highly vascularised granulation tissue provides the oxygen and nutrients needed to sustain tissue synthesis. Cells proliferate. Fibrocytes lay down collagen. White cells remove microbes and dead blood and skin cells. New cells need oxygen, and the oxygen also kills anaerobic bacteria, which are harmful. This requires extra growth of blood vessels, to bring in the cells and extracellular matrix deposition. Skin stem cells migrate from deeper layers in the skin and participate in wound healing.

Keratinocytes renew continuously and migrate upward from the basal layer. Normal epidermal cells from sweat glands and wound periphery re-epithelialize the wound, filling in the defect. Keratinocytes interact with fibroblasts, endothelial cells, immune cells, growth factors and cytokines in a coordinated manner in all phases of wound healing. This tTissue remodelling and re-epithelisation of the wound leads to reconstitution of the physical barrier of the skin.

Baby's direct breastfeeding debrides and cleanses your nipple

Nipple wounds tend to be characterised by sloughing of the non-viable necrotic eschar, a debriding that occurs through either continued breastfeeding or pumping, since it’s typically not possible or desirable to immediately cease drainage of the breast.

A crack, ulcer or other wound on your nipple secretes a healing exudate and then scabs over. You can read about the process of wound healing here. If your nipple wound remains small, baby's direct breastfeeding (if you have decided to continue to offer) automatically debrides or cleanses the wound. Swallowing a small amount of exudate or a small scab won't hurt your baby.

Selected references

Nguyen JK, Huang A, Siegel DM, Jagdeo J. Variability in wound care recommendations following dermatologic procedures. Dermatologic Surgery. 2020;46(2):186-191.