Wound Dressings

What is it?

A wound dressing is a material placed over a damaged area of skin. It doesn't heal the wound by itself. Your body does that. What a good dressing does is create the right conditions for healing.

The main aim is a wound that is moist but not too wet. Wounds make fluid (called exudate), and this is a normal part of repair. But too much, too little or the wrong kind of fluid can slow healing. New skin cells also grow faster in a warm, moist setting, and they only move across healthy, living tissue in the wound.

There are thousands of dressings, and no single one suits every wound. Modern dressings are grouped as passive (such as gauze), interactive (such as films, foams, hydrogels and hydrocolloids) and bioactive. Your podiatrist chooses one based on what your wound is like.

What is it used for?

Dressings are used for almost every kind of wound, including cuts, skin tears, pressure sores, leg ulcers and foot ulcers. For some uses there is better information than for others.

• Closed surgical wounds: silver and DACC dressings probably lower the risk of infection. For other antimicrobial (germ-fighting) dressings, it isn't clear yet. Dressings containing mupirocin (an antibiotic) haven't been shown to help.
• Wounds with a lot of fluid: alginate, hydrofibre, foam and similar dressings are made to soak up large amounts. Hydrocolloids are used for wounds with light to moderate fluid. Hydrogels are commonly used for wounds with dead or sloughy tissue.
• Long-lasting wounds (leg ulcers, diabetes-related foot ulcers, pressure sores): no single dressing has been shown to be best. Foam, alginate and hydrocolloid dressings haven't been clearly shown to beat other dressings.
• Diabetes-related foot ulcers: silver dressings haven't been shown to speed healing. Negative pressure wound therapy (NPWT), a specialised treatment, has mixed results. See "How well does it work?" below.

Is it right for me?

Almost any wound needs some kind of covering, so the question is usually which dressing, not whether to have one. Your podiatrist chooses by looking at the wound bed, how much fluid it makes, and whether it is infected. They also think about your other health conditions, the dressing's features and cost.

Good matches

• Wounds with moderate to heavy fluid suit absorbent dressings such as alginates.
• Wounds with light to moderate fluid suit hydrocolloids.

Poor matches to avoid

• Alginates and hydrofibres on dry wounds or wounds with little fluid. Alginates also aren't suggested for third-degree burns or severe wounds with exposed bone.
• Hydrocolloids on deep wounds, especially infected ones. They also aren't suited to nerve-related (neuropathic) ulcers or very wet wounds. Hydrocolloids with a waterproof backing aren't recommended on infected wounds.
• Hydrogels on very wet wounds or wounds with dead, blackened (gangrenous) tissue, which should be kept dry.
• Any dressing or tape that has caused an allergic reaction for you before. Tell your podiatrist about past reactions.

Special care for the foot and lower leg

If you have a dead, black wound on your foot or lower leg, or a dry, hard, dark patch of skin on your heel that is firmly attached, don't pick at it, soak it or try to remove it. These need your blood supply checked first, and the area should be kept dry. If you have diabetes or poor circulation, have any foot wound checked promptly rather than treating it yourself.

What happens?

Your podiatrist starts by looking at the wound: the wound bed, the type and amount of fluid, and any sign of infection. They aim for a moist but not soggy wound, and they try to keep things simple rather than layering many different products.

The dressing should extend about 2 to 3 cm beyond the edge of the wound. About a third of it sits above the wound and two-thirds below. Some dressings, such as alginates, need a second layer on top, such as foam or a hydrocolloid. If the wound is infected, that top layer shouldn't seal the wound completely.

For a skin tear, your practitioner will line the skin flap back up if possible, hold it with adhesive skin strips and cover it with a silicone foam dressing. If some of the top layer of skin has been lost, they cover that area with a silicone tulle (a thin, non-stick mesh) first.

Your dressing is only part of the plan. The cause of the wound needs treating too. That might mean taking pressure off the area, treating poor blood flow in the leg veins, improving nutrition and managing other health conditions. Without this, the wound is unlikely to heal.

How well does it work?

A dressing helps by managing the wound environment, but it can't fix the cause of the wound, so healing depends a lot on other things. For most dressing types, it isn't clear yet which one gives the best results. Here is what is known for some situations.

• Silver dressings for new diabetes-related foot ulcers in adults: about 75 per cent healed by 12 weeks with non-silver dressings and 69 per cent with silver dressings. Silver didn't add healing.
• NPWT for diabetes-related foot ulcers: in some results it reduced wound size more than other treatment, and in a few it gave better total healing. Other results found it no better than standard moist wound care for closing the wound, and closure rates were low overall. Its benefit is possible, not certain.
• Surgical wounds: silver and DACC dressings probably reduce infection.

Wounds that are healing well usually don't make much fluid. If a wound that should be healing starts making more, it needs another look.

Risks and side effects

Most problems with dressings are local and come from a poor match between the dressing and the wound.

• Allergy: hydrogel, hydrocolloid and silver dressings have been linked to skin allergy. Some adhesives (those containing gelatin or colophony) can cause reactions. Tapes are a common cause. Stop using any dressing or tape that causes a reaction, avoid it in future and ask for a different product.
• Soggy skin around the wound: this happens when a dressing can't soak up enough fluid, such as a thin dressing on a very wet wound. Some alginates and plastic films can also do this.
• Pain or damage when the dressing comes off: alginates can stick to wounds that are dry or have little fluid. Hydrofibres on dry wounds can leave a residue on the wound.
• Overgrown wound tissue (hypergranulation): this may follow long use of hydrocolloids on wet wounds.
• Wound too dry or too wet: a dressing that lets too much moisture escape can dry the wound. One that lets too little escape can let fluid build up.
• Tight layers: keep any top layers and tape snug but not tight, especially if you have poor circulation in your legs.

No severe side effects were reported for hydrogel dressings.

Afterwards

How often a dressing needs changing depends on your wound and how much fluid it makes, and there is no set number of changes. Check the skin around the wound at each change. If it looks soggy or the dressing hurts to remove, tell your podiatrist, as the dressing may no longer suit the wound.

Keep an eye on the wound as it heals. It should slowly shrink and make less fluid over time. Your podiatrist may record its size and fluid at each visit, so a lack of progress is noticed early.

A wound that hasn't improved after about four weeks needs reassessing. Your practitioner may consider a biopsy (a small tissue sample) or a referral to a specialist wound clinic. Alongside this, keep up the other parts of your care: taking pressure off the area, looking after circulation, eating well and managing your other health conditions.

When to see a podiatrist

Book an appointment if

Your wound hasn't improved after about four weeks, or it has taken longer than that to heal, so see your podiatrist or GP. Also book an appointment if the skin around the wound is going soggy, the dressing hurts when it comes off, you need to change it more than three times a day, or the wound is making more fluid when it should be healing. Stop any dressing or tape that causes a rash or itch, and ask for a different one.

Seek prompt assessment if

Call your local emergency number if you have bleeding that is heavy or won't stop, or if your leg, foot or toes suddenly turn cold and pale or blue, with pain or numbness. Also call if you have a wound and feel very unwell, with confusion or slurred speech, severe shivering or muscle pain, severe breathlessness, mottled or discoloured skin, or little or no urine, as this could be sepsis. A fever, chills or feeling unwell with a wound needs urgent medical assessment: see your GP today, or go to an urgent care clinic or the nearest emergency department. The same goes for a wound with an object stuck in it, a bite, or a foot wound that looks to be getting worse quickly. Other signs of infection are more pain, swelling, heat, redness, pus or fluid, or a smell, and you should see your GP or a nurse as soon as you can. If you have diabetes, are older or have a weakened immune system, infection may not show these signs, so have a wound checked promptly if it seems wetter than before. A dead, black wound on your foot or lower leg, or a dry, hard, dark patch on your heel, also needs prompt assessment before anyone removes it.

Frequently asked questions

Is it better to cover a wound or let it air out?

Covering it with a dressing that keeps it moist is now generally preferred. Gauze left to dry can disrupt the healing wound and damage tissue when it comes off. The exception is a dry, black wound on the foot or lower leg or a dry heel scab. Keep these dry and get them checked.

How often should I change my dressing?

It depends on your wound and how much fluid it makes, so there is no fixed schedule. Your podiatrist will tell you what suits yours. As a rough guide, needing a change once or twice a day suggests a mild amount of fluid, two to three times moderate, and more than three times heavy.

Are some dressings gentler for children?

Hydrocolloid dressings are recommended for children's wound care because they don't cause pain when removed. They suit wounds with light to moderate fluid and aren't right for deep or infected wounds. Your child's practitioner can advise which dressing suits their wound.

Further reading

• How wounds heal: MedlinePlus Medical Encyclopedia MedlinePlus
• Wounds, cuts and grazes healthdirect
• norfolk & Waveney CCG wound care Formulary companion and guide NHS
• Changing your dressing at home NHS
• Cuts and grazes NHS