Interpreting skin signs in diabetes

May 20, 2026

Healthcaretoday, Assunta Hospital, Diabetes, Diabetes care, Dermatology, Skin health, skin tags, Diabetes Mellitus, Acanthosis nigricans, Diabetes awareness, Diabetes complications, Metabolic health, Diabetic foot, Skin infections, fungal infections,

Skin tags often occur in areas where friction is common, such as the armpits or inner thighs. They are benign and not cancerous.

Skin is the largest organ in the human body. The surface area of an average adult’s skin is roughly equivalent to the size of one king-size bed. The skin consists of three main layers: the epidermis, dermis, and subcutaneous tissue.

The skin serves several essential physiological functions. These include protection from mechanical injury and infection, sensation, temperature regulation, and vitamin D synthesis.

Classification of diabetes
Diabetes is commonly associated with symptoms such as excessive thirst and abnormal urination.

“Generally we divide diabetes into diabetes mellitus, which is a carbohydrate metabolism disorder, and diabetes insipidus, which is a water metabolism disorder. Diabetes mellitus itself includes gestational diabetes, Type 1, Type 2, Type 3, and monogenic diabetes. The most common form is Type 2 diabetes mellitus, a carbohydrate metabolism disorder that has a high prevalence in our population,” explains Dr Ee Siew Li, Consultant Dermatologist at Assunta Hospital.

Dr Ee presented on “Reading Skin in Diabetes” during Assunta Hospital’s GP Symposium 2026: Diabetes 360: A Multidisciplinary Approach for GPs.

“Red flags to look out for include non-healing wounds, wounds that take longer than usual to heal, recurrent infections such as fungal infections, sudden pigmentation changes, and severe pruritus or xerosis,” says Dr Ee Siew Li while presenting at Assunta Hospital's GP Symposium 2026.

Why skin matters in diabetes mellitus
The skin can act as a visible marker of systemic disease. As many as 70 percent of patients with diabetes worldwide develop cutaneous symptoms.

Early recognition of skin changes is important because it can help prevent complications. In many cases, dermatological manifestations may precede metabolic or vascular complications.

Pathogenesis of skin changes in diabetes mellitus
Persistent hyperglycemia results in chronic low-grade inflammation. This leads to glycation of proteins and subsequent microvascular damage.

Reduced neutrophil activity, including impaired migration and bacterial killing, along with diminished macrophage function and weakened T-cell responses, contributes to immune dysfunction. This impaired immune system increases susceptibility to infections.

Direct nerve damage caused by free radicals generated from a concoction of proteins results in neuropathy. With neuropathy, there is a loss of sensation within the autonomic system, leaving affected areas vulnerable to ulcer formation.

Skin changes by layer
The skin barrier, particularly the epidermis, in patients with diabetes may exhibit abnormal pH levels and mechanical changes. These alterations can increase susceptibility to dysbiosis. The skin may become drier and more porous, and barrier permeability may be altered.

There may also be impaired proliferation, differentiation, and migration of keratinocytes, along with reduced hydration of the stratum corneum.

Another key issue is impairment in cellular regulation and immune function, which contributes to delayed wound healing. Cellular regulation includes immune cell activity in the skin as well as the skin’s reparative processes.

Neuropathy can lead to reduced or lost sensory function, making patients more prone to trauma. Nerve damage affecting blood vessels may alter blood flow regulation. Diminished sweating can result in dry skin, cracks, and fissures.

Common skin manifestations in diabetes mellitus
Skin manifestations associated with diabetes mellitus include infections and metabolic skin changes.

Infections

Bacterial infections such as boils, folliculitis, and cellulitis may occur.
Fungal infections include candidiasis and dermatophyte infections.
Viral infections may include shingles.

Neuropathy-related changes
These include foot ulcers, calluses, and poor wound healing.

Microangiopathy-related conditions
Diabetic dermopathy, often referred to as “shin spots,” is associated with microvascular disease.

Metabolic-related conditions
Acanthosis nigricans is associated with insulin resistance, while necrobiosis lipoidica is another recognized dermatologic condition associated with diabetes.

Skin manifestations strongly associated with diabetes
Acanthosis nigricans is present in approximately 50 percent of patients. However, not all cases of acanthosis nigricans indicate diabetes. In some individuals, it may indicate a predisposition to developing diabetes later in life due to insulin resistance.

“I have seen children as young as five or six years old with acanthosis nigricans. In these cases, I counsel parents to review their family history. It is preferable to encourage a healthier lifestyle, including exercise. Maintaining an ideal body weight is important. Regular health check-ups and blood screening are also recommended, and blood screening is very accessible to us these days,” says Dr Ee.

Diabetic dermopathy occurs in up to 50 percent of individuals with diabetes and is associated with increased cardiovascular risk. Because it is linked to microangiopathy, it can also reflect vascular changes affecting the coronary arteries.

Diabetic foot ulcers and gangrene occur in 19 to 34 percent of individuals with diabetes. Scleredema diabeticorum occurs in approximately 2.5 percent, bullosis diabeticorum in 0.5 percent, while necrobiosis lipoidica is relatively rare at 0.3 to 1.2 percent.

Non-specific skin conditions
Several skin conditions may appear in individuals with diabetes but are not specific to the disease.

Acrochordons, commonly known as skin tags, are one example. Not all skin tags indicate diabetes. Some individuals are genetically predisposed to developing them, while friction may also contribute. Skin tags often occur in areas where friction is common, such as the armpits or inner thighs. They are benign and not cancerous.

Eruptive xanthomas are relatively uncommon in Malaysia. Acquired reactive perforating collagenosis is more commonly seen in patients with end-stage renal failure.

Keratosis pilaris results from the buildup of keratin. This accumulation can form plugs that patients sometimes mistake for abscesses, leading them to attempt removal and subsequently develop infections. Keratosis pilaris is considered non-specific and tends to be more prominent in colder and drier climates. High humidity may make the condition less prominent.

Pruritus and other dermatologic conditions
Pruritus is the medical term for itchy skin. It refers to an uncomfortable sensation that triggers the urge to scratch. Pruritus can range from mild irritation to a chronic condition that disrupts sleep, causes skin damage, and significantly reduces quality of life.

One of the most common causes of pruritus is simple dry skin.

“A lot of chemicals can cause irritation and dryness of the skin, leading to itchiness. Therefore, not all itching is related to diabetes,” explains Dr Ee.

Other skin disorders associated with diabetes include vitiligo, which is more commonly linked with Type 1 diabetes.

Granuloma annulare occurs in approximately 10 to 15 percent of patients. It may appear similar to fungal infections because of its ring-shaped appearance, although the lesions typically lack scaling. Current studies suggest that granuloma annulare has limited clinical impact but may be associated with inflammatory responses related to diabetes.

Lichen planus is present in about 25 percent of individuals with diabetes. Within the Malaysian population, it appears to be more common among individuals with Indian and Chinese skin types and often presents with itching.

“Sometimes we cannot make a diagnosis simply by visual inspection. A skin biopsy may be necessary,” Dr Ee notes.

Cutaneous infections in diabetic patients
Bacterial infections in diabetic patients may include folliculitis, abscesses, impetigo contagiosa, ecthyma, cellulitis, necrotizing fasciitis, diabetic foot infections, and erythrasma.

“Commonly, we see more cases of cellulitis and erythrasma. In mild superficial tissue infections, the most frequently involved pathogens are gram-positive cocci, including Staphylococcus aureus. In deep tissue infections, gram-negative organisms predominate, including Pseudomonas aeruginosa and Enterobacteriaceae,” says Dr Ee.

In some cases of ecthyma, the infection may involve the lymphatic system rather than only the skin.

Dermatologically, ecthyma often has well-defined borders, while cellulitis typically has ill-defined margins.

Fungal infections
Candidiasis is a common fungal infection among diabetic patients. The most prevalent pathogen involved in cutaneous-mucosal candidiasis is Candida albicans.

Common sites include interdigital areas, such as erosions between the fingers or toes, as well as balanitis. Nails may also be affected, leading to paronychia. Mucosal involvement may present as oral thrush or vulvovaginitis.

“To treat a macerated wound around the nail or between the toes, it is important to manage moisture while keeping the area clean. This condition can occur among housewives and doctors as well. Factors such as anatomical changes with age, excessive body weight, and cramped footwear in modern lifestyles can contribute to maceration. Keeping the feet dry is important. This condition is not specific to diabetes but is related to inflammation that can lead to infection, whether bacterial or fungal,” Dr Ee explains.

Tinea pedis is the most common dermatophyte infection among diabetic patients.

Onychomycosis occurs in nearly one in two patients with Type 2 diabetes. It is often overlooked because it may not cause pain, but it can contribute to complications such as cellulitis.

Dermatophytosis and onychomycosis are commonly caused by Trichophyton rubrum and Trichophyton interdigitale.

Skin complications related to diabetes therapy
Skin complications may also arise from diabetes treatment.

Insulin therapy may lead to lipoatrophy, which occurs in 10 to 55 percent of cases. Lipohypertrophy and subcutaneous nodules may occur in approximately 27 percent of patients at insulin injection sites. Local infections may also occur at injection sites.

Insulin allergy occurs in 0.1 to 3 percent of patients.

Oral hypoglycemic agents may also cause cutaneous adverse reactions. These include phototoxic or photoallergic drug eruptions caused by sulfonylureas, which occur in approximately 1 percent of cases. Erythema multiforme may occur with acarbose use, although this is uncommon.

Other reported reactions include leukocytoclastic vasculitis with metformin, psoriasiform eruptions associated with metformin and sulfonylureas, lichenoid drug eruptions caused by sulfonylureas, and pemphigus vulgaris associated with sulfonylureas.

Skin changes in pre-diabetes
Dr Ee highlights that according to the Clinical Practice Guidelines: Management of Type 2 Diabetes Mellitus (6th Edition), HbA1c levels between 5.7 and 6.3 percent indicate pre-diabetes.

Skin changes associated with pre-diabetes are generally non-specific. These may include acanthosis nigricans, skin tags, diabetic dermopathy (shin spots), xerosis or severe itching, slow wound healing, recurrent infections, and thickened or hardened skin.

Red flags in diabetic skin conditions
Certain warning signs should prompt further medical evaluation.

These include wounds that take longer than usual to heal, recurrent infections including fungal infections, sudden pigmentation changes, and severe pruritus or xerosis.

Skin care in diabetes mellitus
Maintaining skin integrity and preventing skin complications are considered the gold standard in diabetic skin care.

Patients with diabetes should use gentle cleansing and moisturizing agents to maintain the skin barrier and prevent dryness, itching, and scaling. These measures may reduce symptoms such as pruritus, erythema, cracking, and lichenification.

Regular skin assessments should be part of routine diabetes care. Skin symptoms may be an early indicator of poor blood glucose control.

“Once diabetes control improves, the skin condition improves and infections become less frequent,” explains Dr Ee.

Patients are also advised to follow proper nail trimming practices and gentle callus removal to reduce the risk of wounds.

Education about proper skin care includes daily cleansing, moisturizing, skin inspection, maintaining good hygiene, and ensuring that areas prone to moisture—such as the feet and inguinal region—are thoroughly dried.

Dermatology recommendations for skin care
The American Academy of Dermatology recommends several measures for individuals with diabetes.

Daily moisturizing helps maintain skin flexibility and prevents cracks that may lead to infection. Creams or ointments are generally more effective than lotions in treating dry skin. Fragrance-free products containing ceramides are preferred.

Dry, cracked heels should be treated using creams containing 10 to 25 percent urea, followed by an occlusive ointment such as petroleum jelly. Wearing cotton socks overnight may help retain moisture.

Gentle cleansers should be used during bathing, as harsh soaps and strong body washes may irritate sensitive skin. Bathing with warm rather than hot water is recommended to prevent excessive drying of the skin.

Skin folds, including areas between the toes and under the arms, should be dried carefully after bathing or swimming to prevent infections.

Patients should also examine their feet daily for discoloration, swelling, scratches, blisters, sores, or cuts. Minor wounds should be treated promptly, while more serious wounds require medical attention.

Calluses should be evaluated by healthcare professionals, as thickened skin may crack and lead to infection.

Patients should seek medical care for skin or nail infections if signs such as swelling, discoloration, tenderness, pus, honey-colored crusts, nail lifting, or nail thickening appear.

All cuts, scratches, and wounds should be treated promptly and kept clean and covered. Toenails should be kept short to prevent irritation and reduce the risk of infection.

Healthy skin reflects systemic health. In diabetes, reading the skin can offer important insights into the disease itself.

Interpreting skin signs in diabetes

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