Diabetes is a serious and increasingly common medical condition that can have major effects on nearly every part of the body, including the skin. With diabetes, persistently high blood sugar levels can alter collagen, damage blood vessels, and impair wound healing, leading to a variety of skin manifestations. Being aware of the potential skin issues related to diabetes can help patients and doctors identify problems early and prevent complications. This article explores 15 ways that diabetes often visibly impacts the skin.
Acanthosis Nigricans: Velvety Dark Patches
One of the most common skin findings in diabetics is a condition called acanthosis nigricans. This causes smooth, velvety, brown or black patches to appear on the sides and back of the neck, under the arms, over the knuckles, and along the creases around the eyes and mouth. The discoloration is not due to excess pigment, but rather to thickening of the skin that results in deeper skin folds.
Acanthosis nigricans is directly related to high insulin levels and insulin resistance. The high insulin binds to receptors on skin cells, stimulating growth and proliferation that leads to thickening. This skin condition often appears before diabetes fully develops and is considered a warning sign of prediabetes or metabolic disease. Treatments like topical retinoids can help reduce thickness, but the condition usually persists until insulin resistance is properly controlled through medications, weight loss, and lifestyle changes.
Yellowing Skin: carotenemia
Some diabetics develop a distinct yellowish discoloration of their skin known as carotenemia. The carotenoids in certain yellow and orange plant foods are normally converted by the body into vitamin A.
But in diabetes, deficiencies in this conversion process lead to a buildup of carotenoids. This, combined with collagen changes from high blood sugar, causes yellow pigmentation. Addressing diet and managing blood sugar levels can help reverse carotenemia.
Shin Spots: Diabetic Dermopathy
Small, round, brown spots on the shins are commonly seen in diabetics. Referred to as diabetic dermopathy or shin spots, these harmless patches often form after minor trauma to the area. The spots persist due to the poor wound healing abilities associated with diabetes. While benign, these spots can signal that diabetes is uncontrolled and identify patients at higher risk for lower extremity complications.
Thick, Tight Skin
Over time, elevated blood glucose can permanently alter the collagen matrix under the skin. This leads to generalized thickening and tightening of skin tissue. Fingers slowly lose the ability to fully extend and palms can no longer press together flat. This condition produces a deformity known as “prayer sign” where hands appear as if palms are pressed together in prayer when attempting to fully extend fingers.
Diffuse skin thickening on the back of the neck and upper back is also common. Although not preventable once damage occurs, improving long-term blood sugar control can help prevent additional stiffening.
This condition appears as raised, red or purple patches that progress to yellow rings with thickened borders. Lesions often start as small bumps on the shins that expand in size over time and can eventually ulcerate. The breakdown is partly related to poor circulation and neuropathy in the lower legs combined with delayed wound healing from diabetes. Steroid injections, anti-inflammatory creams, and other treatments may help reduce symptoms, but necrobiosis lipoidica tends to persist and recurrence is common.
Some diabetics develop sudden crops of yellow, rubbery bumps surrounded by reddish halos, typically on the arms, legs, hands, and buttocks. Known as eruptive xanthomas, these skin lesions are caused by excess lipids (fats) in the blood.
Diabetes often involves high triglyceride levels, and when triglycerides are very elevated, the skin can become overloaded. As diabetes management improves and lipids normalize, the xanthomas usually disappear.
Blisters and Blebs
For uncertain reasons, some diabetics get blisters ranging in size from a pinhead to several centimeters across. Referred to as diabetic bullae, these mysterious blisters seem to develop spontaneously, often on the hands and feet. They may stem from sensory neuropathy causing unnoticed minor trauma, or impairment of sweat glands and oil glands that maintain skin integrity. Careful wound care is needed to prevent infection since the fluid-filled blebs can rupture easily.
Due to atherosclerosis and microvascular disease, diabetics commonly suffer from impaired circulation, particularly in the distal extremities. Combine this with diabetic neuropathy that masks injures, and conditions are ripe for dead skin tissue known as dry gangrene. It typically first affects the toes and can ultimately lead to limb loss. Both meticulous foot care and comprehensive treatment of cardiovascular risk factors are vital to prevent progression.
Sensory neuropathy and poor circulation also produce a tendency for uncontrolled diabetes to cause painful foot ulcers. Minor scrapes or irritations go unnoticed and fail to heal. Pressure sores can appear over points of friction. Ulcers often become infected and can penetrate deep into tissues.
Specialty wound care, orthotics, and sometimes surgery are required to treat diabetic foot ulcers. Prevention includes diligent inspection and protection of feet and consistent blood glucose control.
The hands and feet of diabetics often appear persistently red. This is likely related to improper dilation and constriction of peripheral blood vessels. The underlying mechanism is not fully understood but seems to involve advanced glycation endproducts (AGEs). The stores of sugar in the body react with proteins and fats, forming these inflammatory compounds that can damage blood vessels. Improved glucose control may help reverse reddening.
Diabetics are prone to nail disorders, including nail dystrophy. Nails become brittle, crack, and separate from nail beds. Ingrown toenails and fungal nail infections are also common. Like most skin manifestations, the impact on nails stems from high blood sugar levels impairing microcirculation, nerve function, and normal regeneration of skin cells. Keeping nails neatly trimmed and managing blood sugar helps reduce risk.
Skin-Colored Bumps with Central Plugs
Small skin-colored papules with rough, keratotic (scaly) centers can appear on the lower legs of diabetics with advanced kidney disease. Known as acquired perforating dermatosis, the cause is unknown. Itching and scratching seem to provoke more lesions. When biopsied, the central plug contains collagen and elastin extruded from the deeper dermis to the surface. Topical steroids and oral medications may help resolve lesions.
The high blood sugar, poor circulation, and compromised immunity of diabetes create susceptibility to all kinds of skin infections. Yeasts like candida thrive in the diabetic environment. Signs include red, itchy rashes in skin folds, nail fungus, cracks at the corners of the mouth (angular cheilitis), and oral thrush. Keeping skin clean and dry while maintaining glucose control helps prevent fungal overgrowth. Topical antifungals treat localized infections.
Bacterial skin infections are another concern for diabetics. Bacteria like staph, strep, and pseudomonas can colonize damaged skin and penetrate deeper tissues in the impaired diabetic state. Impetigo, folliculitis, cellulitis, and potentially limb or life-threatening infections can develop from minor cuts or scratches. Careful cleansing of skin wounds along with antibiotics when needed are key to reducing infection risk.
Itchy Rashes from Fungal Infection
Superficial fungal infections like ringworm, athlete’s foot, and jock itch occur frequently in diabetics. The classic scaly, itchy skin rashes stem from fungal types like dermatophytes exploiting vulnerabilities in diabetic skin. Preventing fungal growth through dryness, breathability, cleanliness, and glucose control minimizes occurrence. Antifungal creams clear up most localized cases. Oral antifungal medication may be needed for widespread infection.
A common but lesser-known skin manifestation of diabetes is a persistent red face and neck. Termed diabetic dermopathy, this chronic facial erythema is likely tied to blood vessel abnormalities. Rosacea is sometimes misdiagnosed when facial redness is actually diabetic dermopathy. As diabetes management improves, facial reddening often gradually subsides.
The Skin as an Early Warning
This overview of the skin problems intimately linked to diabetes illustrates that the body’s largest organ provides an outer display of inner health. Recognizing conditions like acanthosis nigricans early can motivate lifestyle changes to restore insulin sensitivity before diabetes takes hold. And catching signs like infections and sores quickly prevents complications in those living with diabetes.
Being attuned to the warning messages conveyed through the skin allows patients and doctors to work together to promote health inside and out. While some skin changes may persist, optimal glucose control gives the best chance to prevent progression and future damage.
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