Test Your Knowledge

Several skin disorders are seen exclusively or nearly exclusively in people who have diabetes. These conditions include:

• Diabetic blisters (also called diabetic bullae or bullosis diabeticorum). Blisters, usually painless, that develop spontaneously on the hands, feet, forearms and lower legs. The lesions contain clear liquid and are not surrounded by redness. These blisters are uncommon, seen most often among men with severe long–standing cases of diabetes. Often diabetic blisters go away on their own within weeks but may reappear. The treatment is controlling glucose (blood sugar) levels.
  
  
• Diabetic dermopathy (also known as shin spots).  Scaly brown patches, usually on the shins, due to changes in the small blood vessels caused by diabetes. These harmless patches do not hurt, itch or erupt and do not require treatment.
  
  
• Diabetic thick skin. Many people with diabetes experience some thickening of the skin. Conditions marked by a pronounced thickening include:
  
  
• Stiff hand syndrome (digital sclerosis). Waxy thickening and tightening of the skin on the back of the hand. The fingers stiffen and lose mobility. Digital sclerosis strikes about one–third of people with type 1 diabetes, according to the American Diabetes Association. In rare cases the elbows, knees or ankles also stiffen. The treatment is controlling glucose levels. Hand stretches and exercises can help.
  
  
• Scleredema diabeticorum  (also called diabetic scleredema). Similar to diabetic sclerosis, except the abnormally thickened skin is on the upper back or back of the neck. Scleroderma diabeticorum is rare. As with diabetic sclerosis, the treatment is controlling glucose levels.
  
  
• Eruptive xanthomatosis. Yellow pea–like bumps, each surrounded by a red halo, that can appear on the skin in cases of uncontrolled diabetes. Eruptive xanthomatosis can itch and usually occurs on the backs of hands, feet, arms, legs and buttocks. It most often strikes young men with type 1 diabetes who have hyperlipidemia (high levels of fat in the blood). However, anyone with diabetes may be affected. Controling diabetes usually resolves eruptive xanthomatosis.
  
  
• Necrobiosis lipoidica diabeticorum (NLD). An irregularly shaped rash similar to diabetic dermopathy but involving spots that are larger and deeper but fewer. Sometimes it begins as a raised reddish area that becomes yellow brown or shiny with a purple outline. The spots can itch, cause pain and break open. NDL is rare, seen more in people with diabetes than nondiabetics, more in women than men, and more in whites than people of other races/ethnicities. It does not need treatment by a physician unless the lesions ulcerate (break open). NLD ulcers have been treated with anti–inflammatory drugs, topical steroids, ultraviolet light and antibiotics.

In addition, many types of skin conditions are more common or more serious with diabetes. These include:

• Bacterial infections. The many types of infectious bacteria include Staphylococcus (staph), Streptococcus (strep) and Pseudomonas. Such infections at one time were life–threatening for people with diabetes, but improvements in antibiotics and glucose control have changed that. Good skin care reduces the risk. Indicators are inflamed tissues that are painful, swollen, red and warm. Precautions should be taken to avoid spreading these contagious conditions, such as not sharing towels. Bacterial infections include:
  
  
• Boil (also called furuncle). Infection of a hair follicle or a gland. Inflammation clots blood vessels and forms a painful red mass. Common sites include the neck, face, breasts, armpits and buttocks. Treatment can include antibiotics, moist heat and incision.
  
  
• Carbuncle. Deep infection and inflammation of the skin and deeper tissue that ends in an area of dead tissue and pus. A carbuncle features a painful node of reddened skin that erupts pus. Common sites include the back of the neck, back and buttocks. Fever can accompany carbuncles. Treatment can include antibiotics, moist heat and incision.
  
  
• Sty. Infection of the glands of the eyelid. Symptoms include pain, swelling of the eyelid and conjunctivitis (inflammation of the mucous membrane lining the lid). Treatment includes topical antibiotics and application of hot packs to encourage drainage.

Boils, carbuncles and styes are painful but often viewed as minor nuisances. If untreated, however, infections can lead to serious complications such as septicemia (blood poisoning).

• Impetigo. A highly contagious inflammatory skin disease caused by staph or strep, characterized by crusty red pustules that erupt. Impetigo is most common around the mouth and nostrils. It usually affects children, but diabetes is one of several diseases that increase its risk in adults. Treatment includes antibiotics and keeping the skin clean and dry.
  
  
• Malignant external otitis (MEO, also called necrotizing external otitis). An uncommon but serious and sometimes fatal infection of the external ear canal that can spread to the facial nerves and to the skull (osteomyelitis). Indicators are severe ear pain that worsens at night and discharge of pus and blood from the ear canal.
  
  MEO is generally caused by Pseudomonas bacteria entering a minor cut in the skin of the ear canal but can be caused by staph infection. It usually affects people with diabetes (especially elders) or other conditions that impair the immune system. Prevention includes avoiding insertion of foreign objects and nonsterile liquids in the ear canal. Treatment may include antibiotics, wound cleaning, surgical debridement and glucose control to help the immune system fight the infection.
  

• Fungal infections. A fungus called Candida albicans causes many of the fungal conditions seen in people with diabetes. Hyperglycemia (high glucose) abets the spread of fungi that exist naturally in the human body. Treatment may include antifungal drugs and control of blood glucose. These infections include:
  
  
• Jock itch. Infection of the area around the penis by candida or other fungi. This condition is common among men with diabetes.
  
  
• Nail fungus (onychomycosis). Usually painless infection of the toenails or, less frequently, the fingernails by any of several types of fungi. The nails can turn yellow, brown, black or gray. Antifungal medications sometimes cannot cure nail fungus. Nail fungus is one reason people with diabetes may need to see a specialist such as a podiatrist for toenail care. Prevention includes wearing absorbent socks, shoes made of breathable material and footwear such as shower shoes in locker rooms and public showers.
  
  
• Ringworm. Infection by Microsporum or Trichophyton fungi characterized by red ring–shaped patches that can scale, itch, blister and cause pain. Ringworm can affect the scalp, beard, nails, chest, abdomen and groin.
  
  Athlete’s foot is a type of ringworm. Athlete’s foot is a contagious, itchy infection that causes cracks in the skin of the feet. It can spread to the toenails and make them thick and difficult to trim. People with diabetes should take athlete’s foot seriously because of the danger of ulcer. Prevention is similar to the measures used to avoid nail fungus.
  

• Thrush. Candida infection of the mouth characterized by white curd–like growths and oral pain. Prevention includes good oral hygiene and controlling glucose levels.
  
  
• Yeast infection. Candida infection of the vagina and vulva is common among women with diabetes.

• Pruritus (itching). People with diabetes often have pruritus because of dry skin, poor circulation, fungal infection or peripheral neuropathy. Scratching an affected area can spread fungal infections. Treatments include limiting baths and showers, using a humidifier and applying a moisturizer.
  
  
• Cellulitis. A broad category of infections, usually bacterial (especially strep or staph) but sometimes fungal, that have spread from the skin to underlying tissues. Symptoms can include fever, headache, chills, low blood pressure and confusion. The skin is warm, red, swollen, tender and prone to blistering.
  
  Cellulitis usually affects the legs and is a serious condition for people with diabetes. If not controlled early it can spread in the body and damage deep tissues, including bone. Because of cellulitis a nick on the ankle can lead to gangrene and foot or leg amputation.

Cellulitis can be prevented, however, through daily skin and foot care and prompt antiseptic treatment of scrapes and other minor wounds. Treatment of mild cases of cellulitis includes oral antibiotics and pain medications. Treatment of advanced cases may involve intravenous antibiotics and removal of dead tissue.

• Acanthosis nigricans. A disease marked by brown or tan raised areas on the neck, armpits and groin and sometimes the hands, elbows and knees. It is associated with insulin resistance, obesity and polycystic ovarian syndrome. Losing weight helps resolve the condition.
  
  
• Disseminated granuloma annulare. Ring–shaped or arc–shaped rash, usually red or reddish–brown, that can itch. It can appear anywhere on the body but usually on areas far from the trunk, such as the hands or ears. The cause is unknown.  Medications prescribed for granuloma annulare include corticosteroids. Ultraviolet light has also been used.
  
  
• Vitiligo. Painless patches of white skin due to destruction of pigment–producing cells. The cause is unknown, but vitiligo has been associated with diseases including diabetes and thyroid disorders. A cure has not been found. Sunscreen should be applied to the affected area to prevent sunburn.
  
  
• Yellow skin and nails. These signs are often noted in people with diabetes. The skin discoloring is most evident on the palms and soles. Yellowing is related to changes in how the body uses glucose.
  
  
• Nephrotic systemic fibrosis or nephrogenic fibrosing dermopathy (NSF/NFD). A rare, poorly understood condition that has recently been found in some patients with kidney disease such as diabetic nephropathy or end-stage renal disease. Symptoms may include areas of hardened skin. NSF/NFD has been linked to high doses of a contrast medium called gadolinium used in an imaging test called magnetic resonance angiography (MRA). The U.S. Food and Drug Administration has approved only the lower doses of gadolinium that may be used in magnetic resonance imaging (MRI).