What skin diseases are associated with diabetes?

Skin Diseases Associated with Diabetes

Diabetic patients experience a wide spectrum of skin manifestations, with fungal infections being the most prevalent (affecting approximately 34% of patients), followed by bacterial infections, and several diabetes-specific dermatoses including acanthosis nigricans, diabetic dermopathy, necrobiosis lipoidica, and scleredema diabeticorum. 1

Fungal Infections

Onychomycosis (Fungal Nail Infections)

• Diabetics are nearly three times more likely to develop onychomycosis compared to non-diabetics, with approximately 34% of all diabetic patients affected 2, 1
• Trichophyton rubrum is the most common causative organism, followed by T. mentagrophytes 2, 1
• The increased risk stems from reduced peripheral circulation, neuropathy, impaired wound healing, and difficulty performing regular foot examinations due to obesity, retinopathy, or cataracts 2, 1
• Untreated fungal nail infections can lead to limb-threatening complications or amputation because diseased nails with thick sharp edges can injure surrounding tissue, creating entry points for bacteria that may go unnoticed due to sensory neuropathy 2, 1

Other Fungal Infections

• Tinea pedis (athlete's foot) frequently coexists with onychomycosis and can spread between the nail and foot 2
• Candida species commonly cause paronychia and infections in skin folds, particularly in diabetic patients 3

Bacterial Infections

Diabetic Foot Infections

• Infections typically begin after breaks in the protective skin envelope at sites of trauma or ulceration 1
• Acute infections in antibiotic-naïve patients are usually monomicrobial, predominantly aerobic gram-positive cocci 1
• Chronic wounds develop complex polymicrobial flora including Staphylococcus aureus, beta-hemolytic streptococci, Enterococci, and Enterobacteriaceae 1
• Methicillin-resistant S. aureus (MRSA) infections are increasingly common and associated with worse outcomes 1

Paronychia

• Frequently occurs in diabetic patients and can rapidly progress to serious hand or foot ulcers 3
• Often involves coexisting Candida species requiring antifungal coverage 3

Diabetes-Specific Dermatoses

Acanthosis Nigricans

• Presents as velvety, hyperpigmented plaques in body folds (neck, axillae, groin) 4, 5, 6
• Represents a sign of insulin resistance and may precede the diagnosis of diabetes by years 5, 6
• Affects 5% of diabetic patients in clinical studies 7

Diabetic Dermopathy

• Appears as atrophic, hyperpigmented patches on the anterior shins 4, 5, 6
• Results from microangiopathy and is associated with chronic hyperglycemia 5, 6
• Found in 0.2% of diabetic clinic patients 7

Necrobiosis Lipoidica

• Presents as yellow-brown atrophic plaques with telangiectasias, typically on the shins 4, 6, 8
• Has unclear strength of association with diabetes but is routinely seen in diabetic patients 5, 8
• Represents granulomatous inflammation with collagen degeneration 6

Scleredema Diabeticorum (Scleroderma Diabeticorum)

• Manifests as thickened, indurated skin on the upper back and posterior neck 4, 5, 6
• Results from increased collagen deposition and glycosylation 5, 6
• More common in patients with poorly controlled, long-standing diabetes 6

Bullosis Diabeticorum (Diabetic Bullae)

• Presents as spontaneous, non-inflammatory blisters on acral surfaces (feet, hands) 4, 5
• Rare manifestation affecting 0.4% of diabetic patients 7
• Associated with long-standing diabetes and neuropathy 4

Granuloma Annulare

• Appears as annular plaques with raised borders, particularly in generalized form 4, 5, 6
• The association with diabetes remains controversial, with unclear strength of evidence 5, 8
• Generalized form found in 0.2% of diabetic clinic patients 7

Other Common Skin Manifestations

Acrochordons (Skin Tags)

• Soft, pedunculated papules in intertriginous areas 5, 6
• Affect 26.2% of diabetic patients and represent signs of insulin resistance 7

Pruritus

• Generalized or localized itching without primary skin lesions 4
• May be related to xerosis (dry skin) from autonomic neuropathy 4

Ichthyosiform Skin Changes

• Dry, scaly skin resembling ichthyosis 5
• Results from autonomic neuropathy causing reduced sweating 1

Keratosis Pilaris

• Follicular keratotic papules on extensor surfaces 5
• Associated with hyperinsulinemia and insulin resistance 5

Eruptive Xanthomas

• Yellow papules on extensor surfaces in patients with severe hypertriglyceridemia 7
• Affects 0.6% of diabetic clinic patients 7

Contributing Pathophysiologic Factors

Neuropathy

• Sensory neuropathy causes loss of protective sensation, leading to unrecognized trauma 1
• Motor neuropathy creates foot deformities and abnormal pressure points 1
• Autonomic neuropathy results in dry, cracking skin from reduced sweating 1

Vascular Disease

• Peripheral arterial disease increases infection risk and impairs wound healing 1
• Microangiopathy contributes to diabetic dermopathy and other skin changes 6

Metabolic Alterations

• Chronic hyperglycemia affects collagen structure and immune function 6
• Hyperinsulinemia drives proliferative skin changes like acanthosis nigricans 5

Clinical Implications and Screening

Dermatologists and primary care physicians must recognize that cutaneous manifestations may be the first presenting sign of diabetes or precede the diagnosis by many years 4, 6. Patients with moderate-to-severe psoriasis should be screened for type 2 diabetes with fasting blood glucose and/or hemoglobin A1C 9. Regular foot examination is essential but may be challenging due to obesity, retinopathy, or cataracts 1. Well-controlled diabetes decreases the prevalence of diabetes-specific cutaneous disorders associated with chronic hyperglycemia 7.