Chronic diabetes affects microcirculation, as well as skin collagen, and cutaneous
problems are common. These include specific manifestations of diabetes, complications
such as neuropathy, skin infections, and cutaneous adverse effects related to treatment.
Type 1 diabetes (autoimmune) is less common than type 2 diabetes (defective insulin
action or secretion).
Skin diseases on diabetic patients :
• Linear periungual telangiectasia without loss of capillary loops— compare with
systemic sclerosis in which capillaries are lost.
• Periungual erythema, ragged cuticles, and tender fingertips.
• Diabetic hand syndrome: scleroderma-like thickening on the dorsum of the hands, with
knuckle pads and papules on periungual skin and the sides of fingers; and sclerosing
tenosynovitis of palmar flexor tendons, with stiffness of MCP and PIP joints. Mild
flexion contractures may limit the ability to press the hand flat on a table or to oppose the
palmar surfaces of fingers. May also have Dupuytren contractures and carpal tunnel
syndrome.
• Diabetic dermopathy or shin spots (round or oval erythematous papules or pigmented
scars on shins). Associated with microvascular complications.
• Feet: neuropathic ulcers (check shoes), onychomycosis, or tinea pedis.
• Necrobiosis lipoidica diabeticorum on shins. May ulcerate.
• Diabetic bullae: asymptomatic bullae on non-inflamed skin. Seen most often on legs
and feet. Cause is unknown, but the differential includes bullous impetigo, PCT, and
autoimmune blistering diseases. Bullae resolve without scarring in 2–3 weeks.
• Vitiligo: well-demarcated, smooth, depigmented macules/patches. Check for other
autoimmune diseases.
• Lipohypertrophy (likealipoma) at sites of insulin injections. Lipoatrophy is uncommon,
since recombinant human insulin introduced.
• Lipodystrophy (acquired or inherited) – very rare cause of insulin resistance with
diabetes and hypertriglyceridaemia.
• Neuropathic itch.
• Eruptive xanthoma (itchy, yellow papules on extensor surfaces and buttocks) associated
with elevated triglycerides.
• Skin tags and (pseudo) acanthosis nigricans: velvety thickening in skinfolds—in obese
patients with insulin resistance and high circulating insulin levels. Insulin has a growth
hormone-like action on skin. Encourage patients to lose weight. Acanthosis nigricans
may respond to a topical retinoid such as 0.05% tazarotene gel. (Also see HAIR – AN
syndrome)
• Scleredema diabeticorum.
• Calcific uraemic arteriolopathy.
• Acquired perforating dermatosis in diabetes with renal failure.