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A white scab is usually caused by trapped moisture, but other possibilities include extended exposure to thick ointments, allergic reactions, and skin infections. Skin cancer and certain autoimmune conditions can also cause skin lesions that look like white scabs, though in these cases there isn’t usually any sort of cut or scrape underneath. Scabs aren’t typically white, and the lack of color is often a sign that something isn’t quite right. People who notice pale-colored wounds or who have skin abrasions that seem to suddenly lose pigmentation should probably seek medical attention if things don’t get back to normal after a day or two.
Water is far and away the most common cause, though in this case the color change is just temporary. Scabs are the body’s way of protecting skin as it heals, basically by creating a natural bandage that “seals” the area from environmental elements and stops surface bleeding. They aren’t impenetrable, however, and water is actually able to seep in relatively easily. Newly formed skin is not attached to the scab, and there is often just enough space in between to allow moisture to get through.
People who take long baths or showers or who spend a lot of time swimming are the most at risk for this sort of discoloration. Water molecules cause the tissues on the skin’s surface to retract and pull away, which can leave scabs seemingly colorless for many of the same reasons that fingers and toes often look pale and wrinkled or prune-like after too long of a soak.
The normal reddish-brown color will usually come back on its own after an hour or so, though people can help the process along by gently drying the area with a soft cloth and leaving it exposed to the air. Moist scabs are usually quite soft and there’s a danger of them lifting away from the skin and separating before the healing process has finished. It can be tempting to put a bandage on the wound to hold things together, but most experts recommend that people hold off until everything is completely dry. As the moisture evaporates, the scab will harden and return to its normal appearance. Removing the soft white material can cause the healing process to start over, increasing the overall healing period and possibly leading to scars or permanent skin damage.
Scabs sometimes also turn white if they’ve been coated in thick ointments or creams for too long. Using first aid creams can be a good idea for wounds, but discoloration is one of the first signs that something isn’t right. Poor air circulation is often the culprit, though allergic reactions and topical skin irritations are also possibilities.
People who cover their wounds in ointments and bandages risk cutting off air flow to the affected area, which can make it harder for the body to heal itself. Scabs don’t always turn white under these conditions, but when they do it’s usually a sign that the area needs more oxygen. Rinsing the wound and allowing it to have regular exposure to the air will often solve the problem.
A person who is allergic to a certain ingredient in a lotion or cream might also experience discoloration, though this is typically caused more by skin chemistry and reactivity than by anything environmental. Most of the time this can be solved simply by discontinuing use of the problematic product, but some people may also need to take antihistamines or other allergy medications in order to help things calm down.
Infected wounds sometimes also have scabs that appear to be white due to the body’s immune response. There are many reasons why a cut or scrape might get infected, but contact with bacterial strains or other contaminants is one of the most common. When this happens, the skin around the wound will often be red and hot to the touch, and pus may ooze from underneath the scab. In most cases it’s the puss that makes the scab look white; when this is drained, most people see that the red-brown color was actually still there all along.
Most minor infections can be treated with a topical antibiotic ointment and clean bandages, but anyone who notices puss or oozing from their wounds should seek medical attention. Infections are often more serious than they seem at first, and can spread if not properly treated.
Sometimes white lesions suddenly appear that look like scabs but in places that haven’t recently been scraped or cut. People who notice these on their bodies should usually consult a healthcare professional right away, since some skin cancers take on this appearance in the early stages. Medical experts can biopsy the lesions in order to determine if they were caused by cancer or some other skin condition. Herpes and human papillomavirus, for instance, can also cause small, white spots that may look like white scabs at first.
Most experts recommend a “wait and see” approach to white scabs. People are usually advised to keep the area clean and dry, then watch it for a day or two. If the color doesn’t return or if the area gets paler, grows inflamed, or becomes painful, medical attention is usually necessary.
@wander - You sure sound like you have an infection in your knee and you really need to get that taken care of. I wouldn't bother the doctor with it though unless you have a fever.
If you go to the pharmacy buy some iodine or hydrogen peroxide to clean your cut, then get some over-the-counter antibiotic cream for it. Slap a bandage on it and it should be fine in no time.
I am pretty accident prone as well, and I always need to patch myself up, especially after playing sports. All you need to do is keep your cut clean for the next few days, and if it starts to look red and inflamed, head to the doctor.
What should you do if you end up removing a white scab by accident?
I fell down rollerblading last week and made a mess of my knees. I noticed earlier that there was a white part, and didn't think anything of picking it off. Now it is bleeding again and looks a bit like there might be an infection there.
Do you think that I should go to the doctor's for some antibiotics, or can I get something at the pharmacy?
I can definitely see what was causing the scab to look white now and it isn't very pleasant. I hate getting scraped.
When I was swimming I noticed that I had a white scab and it really freaked me out. I thought for sure something horrible had happened to my cut, but after I dried it off it went back to its normal color.
I think if you have any cuts that are really worrisome you should avoid swimming for awhile. I am not sure if the chlorine in the pool did my scabs any good, but the water certainly made them look odd. I am glad I didn't go with my first instinct and try and pick off the white scab. I am sure that would have just made my problems much worse.