Diabetic Skin Conditions: Rash, Blisters & More

Diabetic Skin: Protecting Your Outermost Layer

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The phrase “feeling comfortable in your own skin” is usually used figuratively to describe a level of self-confidence or self-acceptance. But when your skin itches, hurts, flakes, breaks out, changes color, or just doesn’t look or feel the way you’d like it to, the phrase can take on a new, very literal meaning.

Diabetes can affect the skin in a number of ways that can make a person feel less than comfortable. In fact, as many as a third of people with diabetes will have a skin condition at some point in their lifetime. While some conditions may appear uniquely in people with diabetes, others are simply more common in people with diabetes. The good news is that a fair number of these conditions are treatable or can be prevented by maintaining blood glucose control and taking good daily care of your skin.

The Skin

Dry, itchy diabetic skin

Dry skin can occur as a result of high blood glucose. When the blood glucose level is high, the body attempts to remove excess glucose from the blood by increasing urination. This loss of fluid from the body causes the skin to become dry. Dry skin can also be caused by neuropathy (damage to the nerves) by affecting the nerves that control the sweat glands. In these cases, neuropathy causes a decrease or absence of sweating that may lead to dry, cracked skin. Cold, dry air and bathing in hot water can aggravate dry skin.

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Dryness commonly leads to other skin problems such as itching (and often scratching), cracking, and peeling. Any small breaks in the skin leave it more exposed to injury and infection. It is therefore important to keep skin well moisturized. The best way to moisturize is to apply lotion or cream right after showering and patting the skin dry. This will seal in droplets of water that are present on the skin from the shower. Skin that is severely dry may require application of heavy-duty emollients 2—3 times a day.

Itchy skin is usually related to dryness, but it can also be related to poor circulation, especially in the legs and feet. This is typically due to atherosclerosis, a disease in which fatty plaques are deposited in the arteries. Fungal infections, which can be more common when a person has high blood glucose, can also be very itchy.

Bacterial infections with diabetic skin

When blood glucose levels are high, a person with diabetes is more susceptible to infection. This is believed to be why there’s a higher incidence of certain bacterial infections among people with diabetes and why these infections tend to be more serious than in the general population. The following are some of the more common bacterial infections in people who have diabetes.

Impetigo and ecthyma

Impetigo is a common, contagious, superficial skin infection that starts out as fluid- or pus-filled blisters or pimples that rupture to form erosions on the skin. These erosions are then covered by crusts. Minor breaks in the skin may lead to an impetigo infection, or it may arise as the result of an existing skin problem, such as atopic dermatitis, contact dermatitis, psoriasis, ulcers, traumatic wounds, burns, or insect bites. This infection most often arises on the face, arms, legs, buttocks, hands, and skin folds such as the underarms and groin.

Ecthyma has many features similar to those of impetigo and can in fact result from untreated impetigo. The main difference is that ecthyma goes into the deeper layers of the skin, forming ulcerations, which then become covered with thick crusts. This condition most commonly occurs on the legs and sometimes the buttocks. Poor hygiene increases the risk of ecthyma.

Impetigo may improve on its own, or it may become chronic and widespread. The use of oral antibiotic medicine, coupled with topical antibiotics such as bacitracin, antibacterial soaps, and good hygiene, is typically sufficient to clear the infection within a week. Ecthyma is usually treated the same way but for a longer period of time; generally, antibiotics are taken for 10—14 days. Since lesions (areas of damaged tissue) are deeper in ecthyma, they usually take a longer time to close, and they may heal with some degree of scarring.

Folliculitis, furunculosis, and carbuncles

Folliculitis, furunculosis, and carbuncles are all infections that arise in the hair follicles. Sweat and other conditions that cause moisture on the skin (such as high temperatures and humid weather), the shaving of hairy regions such as the underarms and legs, and the blockage of hairy areas by clothing, bandages, or casts or by lying or sitting in one spot for a long period of time can all increase the risk of an infection in the hair follicles.

Folliculitis is inflammation of the hair follicle that is characterized by the formation of a pustule (a small pimple or blister containing pus) or a group of pustules. Furunculosis is distinguished by the development of furuncles – deep, red, hot, tender nodules – that may develop from the pustules found in folliculitis. The nodules usually enlarge, become painful, and rupture after several days, forming abscesses (swollen areas containing pus). Furuncles generally occur on the neck, face, underarms, and buttocks. A carbuncle is a larger, painful, more serious lesion with a deeper base, generally occurring at the nape of the neck, on the back, or on the thighs. The area is red, swollen, and covered in pustules. Fever and a feeling of illness may also occur with a carbuncle.

The chances of getting folliculitis may be lessened by using clean or new razors to shave, exposing areas of the skin that are typically covered, such as the back, to the air, and wearing loose, cool clothing. Lesions usually improve on their own, but they heal faster with the use of antibiotic washes and creams. Simple furunculosis is treated by the local application of antibiotic creams and warm, moist compresses, which relieve discomfort and promote drainage. A carbuncle or furuncle with a significant amount of redness or swelling or an associated fever should be treated with a systemic antibiotic (one that affects the entire body), since one of the risks of these lesions is an infection of the bloodstream. This can spread bacterial infection to many of the body’s organs, including the heart, brain, and kidneys.

When the lesions are large, painful, and fluctuant (they can be shifted and compressed), draining them via surgery is usually the best option. In these cases, the person should receive antibiotics until all evidence of inflammation has disappeared. After the lesion is drained, the area should be covered with a thin layer of antibiotic ointment and a sterile dressing.

Cellulitis and gangrene

Two of the more serious and complicated bacterial infections that occur in people with diabetes include cellulitis and infectious gangrene. Cellulitis is an infection that spreads through the deeper layers of the skin as well as the fat layer directly underneath the skin. People who develop cellulitis usually have an open wound that acts as an entry point for bacteria, although occasionally, the skin infection originates from a bacterial infection of the blood. Areas infected by cellulitis are typically red, warm, painful, and swollen. The lesions feel hard to the touch, and there is no clear line between skin that is infected and skin that isn’t infected. This condition usually affects the face and extremities, and sometimes it also occurs on the trunk. The legs are affected three times more often than the arms.

Cellulitis requires prompt medical care. It is important that the health-care provider take a culture to determine what organism is causing the infection so that the right antibiotic is used. Once oral or intravenous antibiotics are started, the average time for healing is 12 days, with a range of 5—25 days.

Infectious gangrene is a serious condition that usually develops on the hands or feet at the site of an injury such as a laceration, needle puncture, or surgical incision. It can also occur in surgical incisions on the abdomen. The condition generally begins as cellulitis, which is followed by fever and other generalized symptoms as the infection rapidly spreads. The area then becomes dusky blue in color, and blisters appear and rupture, forming areas of black skin.

Since the mortality rate (death rate) for infectious gangrene is high, it is important that it is diagnosed early and treated aggressively.

Fungal infections with diabetic skin

High blood glucose levels can also predispose people with diabetes to developing common fungal skin infections from organisms such as Tinea and Candida.

Fungal infections can occur just about anywhere, including the feet (Tinea pedis), the hands (Tinea manuum), the body (Tinea corporis), and the groin (Tinea cruris). Tinea pedis, or athlete’s foot, usually occurs in the web spaces between the toes or on the soles of the feet. Lesions are itchy and may develop vesicles (sacs filled with air or fluid) or may simply be red and scaly. It is usually contracted by walking barefoot on a contaminated floor. To help prevent athlete’s foot, it is always a good idea to wear slippers or shoes of some sort in public areas such as locker rooms. Tinea manuum is characterized by papules (small, raised pimples or swellings), vesicles, or scaling, typically on the dominant hand, and is associated with touching athlete’s foot lesions. Tinea corporis, or ringworm, presents as multiple red or pinkish circular lesions with a distinct, scaly border. In severe cases, the lesions may merge, forming large, discolored areas on the body. Tinea cruris, or jock itch, results in red to brownish, scaly, itchy lesions that cover the groin and sometimes extend to the pubic region and upper thighs.

Candidiasis of the skin tends to occur in folds of skin such as the underarms, groin, under the breasts, and between the buttocks. This condition begins with pustules on a red base that eventually result in softened, thickened areas of skin.

All of these superficial fungal infections are treated in more or less the same way. Applying antifungal creams two to three times daily for approximately two to four weeks should clear the infection. Keeping the affected areas dry, and using medicated powders in skin folds to reduce friction and moisture are also helpful measures. Infections that don’t respond to topical treatment may be treated with oral antifungal medicines.

Skin conditions associated with diabetes

The following skin conditions are strongly associated with having diabetes, but they can occur in people who don’t have diabetes as well.

Acanthosis nigricans

This condition is characterized by the formation of velvety, brownish, thickened areas of skin in the groin, underarms, under the breasts, and in the creases of the neck. The affected skin may become leathery or warty or develop tiny skin tags. Acanthosis nigricans is common in people who are obese, but it may also be associated with certain forms of cancer as well as endocrine disorders such as polycystic ovarian syndrome (PCOS), acromegaly, Cushing syndrome, and diabetes.

There is no cure for this condition, but it may improve with weight loss, topical bleaches, or a class of drugs known as keratolytics.


Vitiligo is a skin disorder that causes white spots or large areas of depigmentation to occur on various areas of the body. About 30% of people with vitiligo have a family history of the condition, and it is more common in people with Type 1 diabetes than Type 2 diabetes. Vitiligo progresses slowly over the years, commonly affecting the backs of the hands, the face, and body folds such as the underarms and groin.

Treatment of vitiligo is necessary only in people who have severe cases or who are considerably distressed by the condition. Treatment involves the use of steroids or chemical agents called psoralens that are either placed directly on the skin or taken orally. The most popular treatment, known as PUVA, uses oral psoralens in combination with phototherapy sessions, in which the person is exposed to ultraviolet light, specifically ultraviolet A.

Granuloma annulare

A common skin disorder of unknown cause, granuloma annulare manifests as skin-colored or pinkish groups of bumps, or papules, that may be arranged in rings. There are several subtypes of granuloma annulare; the one associated with diabetes is called disseminated, or generalized, granuloma annulare, in which lesions are widespread over the body. The use of steroid creams or ointments or steroid injections is sometimes used to treat lesions. Most, however, disappear on their own within two years.

Diabetes-related skin conditions

The following skin conditions occur almost exclusively in people who have diabetes.

Diabetic dermopathy

This common skin condition is characterized by depressed, irregularly round or oval, light brown, shallow lesions. Lesions may vary in number from few to many and are usually found on both legs but are not symmetrically distributed. Because these lesions do not itch, hurt, or open up, they are often overlooked and not reported to the health-care provider.

Diabetic blisters (bullosis diabeticorum)

This is an uncommon condition in which blisters occur on the hands and feet and sometimes also the legs and forearms. The blisters are unrelated to trauma or infection; they develop spontaneously and may become quite large. However, they are usually not painful and typically heal without scarring in several weeks.

Foot ulcers

Foot ulcers are a serious problem that can ultimately lead to amputation if left untreated. Each year, about 2% to 3% of people with diabetes develop a foot ulcer. Approximately 15% of people with diabetes develop a foot ulcer at some point in their lifetime.

Foot ulcers are erosions on the skin of the feet. Some affect just the outermost layers of skin, while others extend to deeper tissues. Ulcers often begin as a result of minor trauma, such as irritation from ill-fitting shoes that goes unnoticed or untreated. The most common locations for ulcers to develop are the weight-bearing areas of the foot such as the heel and the ball of the foot and sites subject to pressure such as the toes or ankles.

A number of factors make people with diabetes more likely to develop foot ulcers than those without diabetes. Neuropathy is one risk factor. Almost all people with diabetes who develop typical foot ulcers have neuropathy that affects their motor, sensory, or autonomic nerves. Neuropathy in the motor nerves causes weakness, thinning, and limitation in the movement of certain muscles in the foot, leading to deformities in the normal foot shape such as atypically high arches, claw toes (all toes except the big toe bend toward the floor) and hammer toes (the longest toe bends toward the floor at the middle toe joint). Neuropathy of the sensory nerves results in loss of protective sensation to pain, pressure, and heat. People with sensory neuropathy may therefore not be aware of cuts, abrasions, and calluses that can lead to ulcers. Depending on the amount of sensory neuropathy, people may even be unaware of major traumas to their feet, such as occur from stepping on pins, glass, and other sharp objects. Neuropathy of the autonomic nerves can lead to warm, excessively dry feet that are prone to skin damage.

Peripheral vascular disease is another factor that can contribute to the formation of foot ulcers in people with diabetes. Because of the decreased blood circulation to the feet in this condition, there is an impaired delivery of oxygen, nutrients, and antibiotics. Therefore, wounds tend not to heal well and to become infected.
Foot ulcers warrant immediate attention and treatment. The physician will need to determine how deep and infected the ulcer is. He may take an x-ray of the foot to check whether infection has spread to the bone. Treatment for a foot ulcer may include oral or intravenous antibiotics to control the infection, as well as dressings and salves with lubricating, protective, antibiotic, or cleansing properties. Taking care of the ulcer and following up with health-care providers is very important for preventing complications that could eventually lead to an amputation.

Necrobiosis lipoidica diabeticorum

This condition occurs in about 0.3% of people with diabetes and is three times more common in women than in men. Lesions tend to form on the fronts and sides of the lower legs, although they may also occur on the face, arms, and trunk. The typical lesion begins as a tiny, dusky red, elevated nodule with a defined border. It gradually enlarges, becoming irregular in shape. It may then become depressed and turn a brownish-yellow color, except for the border, which remains red. Affected areas may lack sensation because of the destruction of some nerves and nerve endings.

The course of this condition is usually chronic and recurrent. Although topical steroids may halt progression of active lesions, it is very difficult to completely cure the affected areas. Untreated lesions can readily deteriorate to form shallow, painful ulcers. Unfortunately, not even the normalization of blood glucose levels is sufficient to control this skin condition in many cases.

Digital sclerosis and scleredema audoltorum

Digital sclerosis is a condition in which the skin on the hands becomes thickened and waxy and may develop multiple, pebble-like growths. Scleredema audoltorum is a similar condition that affects the back and sides of the neck, with the possibility of painless swelling spreading to the face, shoulders, and upper torso.

Although there is no effective treatment for these conditions, they generally resolve on their own within six months to two years.

Saving your skin

To protect your skin and help prevent skin ailments from developing, observe good hygiene. Bathe regularly and wash your hands often. Keep areas of the skin that are susceptible to infections, such as the underarms, groin, area under the breasts, neck, web spaces of the feet and hands, and inner thighs clean and dry. If necessary, use antichafing powders or creams and choose proper clothing that allows air to circulate. After bathing, dry these areas well to prevent infections from beginning. People who live in hot, humid areas should change their clothing once it becomes wet from perspiration.

Be sure to use mild or hypoallergenic varieties of products that come in contact with the skin, such as soaps, lotions, washes, and creams. Products with additives such as fragrances or coloring can irritate the skin or cause an allergic reaction.

Diabetes rashes

Also keep an eye out for skin reactions that arise as a result of allergies to medicines. Reactions to oral drugs may take the form of itching, rashes, or wheals, while reactions to insulin may appear as bumps, rashes, or depressions in the areas where insulin is injected. If you suspect you are allergic to one of your diabetes drugs, inform your health-care provider.

Wounds should be treated promptly. Since people with diabetes may not heal as well as others, it is important to give immediate attention even to cuts and wounds that seem minor. Injuries to the skin should be kept covered and inspected on a regular basis to make sure they are not worsening. The hands and feet should be inspected daily for the presence of cuts or scrapes, since these parts of the body may have decreased sensation due to neuropathy, and wounds may therefore go unnoticed. Dryness and itching can be self-treated, but more serious conditions should be brought to the attention of a doctor.

Preventing foot ulcers

Proper foot care is a vital part of preventing minor wounds from developing into ulcers. This means the feet should be inspected daily for cuts, sores, or other forms of irritation. The toenails should be cut straight across. (If a person cannot see or reach his feet, a health-care provider should cut his toenails.) The feet should be washed daily in warm water and carefully dried, especially between the toes. A moisturizing lotion should then be applied, but not between the toes.

A health-care provider should examine the feet at least once a year. People with risk factors for developing a foot ulcer, such as neuropathy, foot deformities, calluses, or a history of foot ulcers, should have their feet inspected by a doctor more often, preferably every one to six months. If a person notices a blister, cut, scratch, sore or other form of irritation, he should be sure to notify his health-care provider immediately.

People with diabetes should avoid walking barefoot, even when indoors. Socks or stockings should also be worn to reduce friction between the foot and the shoe. If possible, choose seamless socks and stockings. Socks with lumpy seams can be worn inside out to prevent irritation to the skin.

Wearing shoes that fit is very important, since ill-fitting footwear is a major cause of foot ulcers. People who have not lost the protective sensation in their feet can choose off-the-shelf shoes. Shoes should have some room, preferably 1/2—5/8 inch, between the front of the shoe and the longest toe. The width of the shoe should accommodate the ball of the foot, and the toes should not be cramped. Selecting a store with a certified pedorthist on staff is a good idea, since this person will know the subtle differences between various styles. It is best to select shoes toward the end of the day, when feet are at their largest.

People who have lost the protective sensation in their feet due to neuropathy or those who have peripheral vascular disease, foot deformities, calluses, ulcers, or other special circumstances should discuss getting customized shoes with their physician.

The skin you’re in

A large part of keeping your skin healthy involves maintaining practices that are good for your whole body, such as eating a balanced diet, drinking plenty of water, managing stress, and controlling your blood glucose level. Good diabetes management is especially important, since many skin conditions are related to complications resulting from high blood glucose. By sticking with healthy habits and keeping an eye on your skin, you can avoid many common ailments and be happy with the skin you’re in.

Originally Published August 13, 2009

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