It’s common knowledge that wounds tend to itch as they heal. This irritating sensation is familiar to anyone who has ever had a cut, scrape, burn, or insect bite. But why exactly do healing wounds cause itchiness?
The itching is related to the complex biological processes that occur as the damaged skin repairs itself. As the wound heals, new tissue forms and nerve endings regenerate. This regeneration process can stimulate nerves and cause itching or tingling. Additionally, histamines and other chemicals produced during the healing response can trigger itchiness. Understanding the science behind wound healing itch can help you find relief.
The Biology of Wound Healing
Healing begins immediately after injury as several biological processes spring into action:
Inflammation Phase
First is the inflammation phase, which starts immediately after injury. Damaged blood vessels constrict to limit blood loss. Platelets and proteins quickly clog the wound, forming a clot. This triggers an inflammatory response as white blood cells, immune cells, and proteins rush to the wound to fight infection and begin the healing process.
During this stage, histamines are released, causing fluid leakage and swelling. Histamines also provoke itching and pain.
Proliferation Phase
Next is the proliferation phase, which begins 2-10 days after injury. In this phase, fibroblasts produce collagen to mend the wound. New blood vessels form to reconnect blood supply to the area — a process called angiogenesis. Epithelial cells multiply and crawl across the wound bed, covering it with new skin.
Nerve endings are also re-growing during this time, which can cause tingling and itching sensations.
Maturation Phase
Finally, the maturation phase can last for a year or longer as the new tissue strengthens. Swelling goes down as cells below the dermis reconstruct the supportive matrix. Collagen fibers crosslink to increase tensile strength. The new skin never regains the original elasticity or strength.
During this prolonged remodeling, nerve endings can become hypersensitive, leading to chronic itchiness.
Why Wound Healing Causes Itching
With this basic biology in mind, here are some specific reasons why healing wounds often itch:
Nerve fiber regeneration
As a wound heals, nerve fibers regrow to reestablish sensation in the damaged skin. This regeneration process can provoke feelings of itchiness or tingling. Nerves send mixed signals that get misinterpreted by the brain as itch.
Histamine release
Histamines are chemicals released by immune cells during the inflammatory phase. They help widen blood vessels to bring more infection-fighting cells and proteins to the wound. But histamines also bind to receptors on nerve cells, triggering impulses that the brain interprets as itchy.
Prostaglandins
Prostaglandins are messenger molecules produced at the wound site that play various roles in healing, like stimulating collagen formation and encouraging new tissue growth. But they can also provoke itching by binding to nerve fiber receptors.
Growth factors
Growth factors like FGF-2 direct new tissue formation. But in addition to stimulating regeneration, they can also latch onto nerve fibers and induce itching.
Neuropeptides
Neuropeptides are molecules generated by nerves that help regulate the healing process. But some may also provoke itch signals. Substance P is one that may play a role in wound-related itching.
Dry skin
Scabbing and dryness around a healing wound can provoke itching. As new skin forms underneath, the layers can flake and crack. These subtle disturbances in the epidermis can set off itch signals.
Why Wound Itching is Healthy
Though unpleasant, some degree of wound itching is normal and even beneficial during healing. Itching can indicate that the regeneration process is underway as nerves regrow in the damaged tissue.
Mild itching prompts scratching and rubbing that may help:
– Shed dead skin cells to promote new growth
– Enhance blood flow to bring oxygen and nutrients
– Release growth factors that stimulate tissue regeneration
– Distribute healing cells and proteins evenly through the wound
So some wound itching can support the healing process. However, severe itching can impede healing and increase risks like infection. Finding the right balance is key.
Treatments for Itchy Healing Wounds
While low-level wound itching can be beneficial, severe itching warrants treatment for comfort and to prevent disruption of the healing process. Here are some effective remedies:
Cold compresses
Applying cold, wet compresses to the wound can relieve itching by desensitizing nerve fibers. The cold also reduces inflammation.
Corticosteroid creams
Over-the-counter hydrocortisone creams contain steroids that reduce inflammation and itching. Low-dose creams are appropriate for healing wounds.
Antihistamines
Oral antihistamines like Benadryl block the action of itch-inducing histamines. Topical creams containing antihistamines are also available.
OTC anti-itch creams
Look for creams containing soothing ingredients like oatmeal, menthol, zinc oxide, or vitamin E. Many combine antihistamines and anesthetics for fast targeted itch relief.
Moisturizers
Hydrating the skin with thick moisturizing creams can relieve itching caused by dry, cracking skin around the healing wound.
Dressings
Bandages, films, or hydrogel sheets create a protective barrier while keeping the wound moist to prevent scab itching.
Pain relievers
Over-the-counter pain pills like acetaminophen or ibuprofen have mild anti-itch effects by blocking pain/itch signals.
Antibiotics (if needed)
For signs of wound infection like increasing pain, swelling, redness, or pus, see a doctor for oral or topical antibiotics to treat infection and reduce associated itching.
Medications for chronic itching
For severe chronic wound itching, prescription medications may be warranted. Topical numbing creams, anti seizure meds, antidepressants, and immunosuppressants can reduce itchiness.
When to See a Doctor
Contact your doctor if:
– Wound itching becomes severe or persistent
– Itching is accompanied by signs of infection
– Over-the-counter remedies fail to provide relief
– The wound shows signs of poor healing like increasing pain or slow closure
A doctor can assess the wound, provide stronger prescription treatments, and rule out complications interfering with proper healing.
Conclusion
Itching is a common side effect of the complex wound healing process. As nerves regenerate and skin reforms, itching and tingling frequently occur. Chemicals produced during healing like histamines, prostaglandins, and growth factors can also spark itch signals by binding to nerve fibers. Mild wound itching can be beneficial for healing, but severe itching warrants treatment. Cold compresses, topical steroid creams, antihistamines, moisturizers, wound dressings, and pain relievers can relieve itchiness and allow wounds to heal properly. See a doctor for severe, chronic, or worsening wound itching.