Overview

The fuel our body needs to function is glucose. In diabetes, the body loses its capacity to use this fuel. This leads to increased sugar levels in the blood. Diabetes mellitus is a common endocrine disorder affecting various populations worldwide.

Diabetes manifests itself in all organs of the body. It manifests in the skin as an irritating sensation of scratching called pruritus. Here, we will look into the cause, effects, treatment, and prevention of pruritus in people with diabetes.

Classification of pruritus.¹ Chronic pruritus is classified into the following types based on its aetiology (underlying cause):

Dermatologic: Resulting from skin diseases, such as atopic dermatitis, dry skin, etc.

Systemic: Resulting from disease of organs other than skin, such as kidney (renal failure), blood (Hodgkin’s disease), etc.

Neurologic: Resulting from disorders or diseases of the central or peripheral nervous system, such as nerve irritation, nerve damage, etc.

Psychogenic:

Mixed: Simultaneous occurrence of several diseases

Other: Chronic pruritus of undetermined origin

Common causes of pruritus

Conditions of skin 

Eczema, psoriasis, dry skin, insect bites, hives, etc.

Allergic reactions 

Adverse reactions to medicines, cosmetics, or any substance (such as poison ivy) cancause inflammation, redness, and itching.

Infections 

Bacterial or fungal infections are the primary reasons. Scabies causes a persistent itch that is contagious. 

Insect bites

Stings of mosquitoes and bees cause urticaria, redness, and itching.

Systemic diseases 

Obstructive jaundice presents itself as itching. 

Cancer 

Hodgkin’s lymphoma

Pruritus and diabetes

Although pruritus is associated with diabetes mellitus, stating that diabetes causes pruritus is controversial.²

The itch-scratch cycle is initiated when we scratch, damaging the skin, and releasing inflammatory chemicals that intensify the itch, causing more scratching.

Prevalence

One out of every five patients with diabetes suffers from cutaneous (skin) infections. A poor defence mechanism makes our body more susceptible to infections. 

Patients lacking control over blood sugar levels are more susceptible to infections than the rest of the population.³

Some common skin manifestations of diabetes³

Acanthosis nigricans are patches of grey to brown colour with velvety or verrucous texture found on the back of the neck, axilla, or palmar hand.

Diabetic dermopathy is pigmented patches that develop in the pretibial region (lower leg).

Diabetic foot syndrome starts with callus formations, and dry skin ulcers develop later with several other malformations of the feet.

Predisposing factors 

• Dry skin (skin xerosis)
• Polyneuropathy

      Some other conditions developing due to elevated blood sugar may also produce an itch.⁴

Causes of pruritus in diabetic patients 

Dry skin (xerosis)⁵

Our skin is the largest organ in the body and is also the body’s first protective barrier. A compromised barrier makes the skin susceptible to infections. 

The lipids within the skin prevent dehydration and the natural moisturizing factors help in absorbing water. ⁽⁶⁾ High blood sugar levels draw out water from the skin, causing the skin to dehydrate. Diabetes is responsible for skin infections, as the underlying mechanism of the skin to protect itself fails. 

In healthy skin, the nerve fibres extend up to the dermo-epidermal junction. It means nerves lie deep into the skin tissue. In patients with diabetes, more nerve fibres are present in the epidermis (outermost layer of skin) region i.e. they come to lie superficial in the skin.⁶ These nerves get fired and cause itching. 

Poor circulation

With more glucose circulating in the blood, the viscosity of the blood increases in diabetes. The availability of nutrition and oxygen decreases in body parts situated farther away. This results in damage to the nerves and neuropathy. Polyneuropathy (malfunction of peripheral nerves) causes itching. In diabetes mellitus, nerves in the legs are vulnerable to nerve damage and so the patient experiences unpleasant sensations.

Infections

Diabetic patients lack immunity- they acquire bacterial and fungal infections on the skin that cause itching.

Other reasons include medications: long-term use of metformin causes itching. Itching can occur as an allergy to a medicine recently added.

Kidney and liver damage also present as itching. However, that occurs with additional symptoms of urination and jaundice.

Impact of pruritus

The chronicronic itch causes

• Anxiety and depression
• Mood disorders
• Psychiatric illness

Precautions: keeping diabetic’s skin healthy

Maintain optimal blood sugar levels.

Avoid hot water baths as it dries the skin.

Moisturize skin immediately after a bath when the skin is still wet. Avoid lotion in web spaces of toes as this can promote fungal growth.

Use hypoallergenic or gentle moisturizers: avoid moisturizers with harsh perfumes and chemicals.

Treatment⁶

Antihistamines 

Relieve itching due to dry skin.

Emollient 

Application reduces itching due to dry skin. 

Phototherapy 

Ultraviolet (UV) light-based therapies such as PUVA and narrow-band UV B (NB-UVB) reduce chronic pruritus. Phototherapy reduces nerve-firing in the epidermis). Excimer lasers also treat chronic pruritus.

Neurotrophin

The inflamed skin of rabbits produces non-protein chemicals called neurotropins. They are used to treat antihistamine-resistant pruritus.

Phospholipids

Phospholipids in milk improve the hydration of the skin and skin barrier functions. 

Antioxidants 

Are applied topically over the skin; they prevent dry skin-induced itching.  

Film dressing 

Film dressings applied over wounds prevent skin dryness that results from the removal of adhesives extending over to the skin.

Corticosteroid 

Topical applications relieve itching.

FAQ’s

Does diabetes cause pruritus?

Most people believe that pruritus is due to uncontrolled diabetes. This, however, is difficult to say.

How can diabetic neuropathy be prevented?

The simplest way to prevent neuropathy is to control your blood sugar level. 

Taking metformin for a long duration lowers vitamin B12 and causes neuropathy. Vitamin B12 levels in the blood need regular monitoring.

Why do people with diabetes develop fungus?

Because high blood sugar levels in blood provide breeding grounds for fungus, it develops in folds of skin, mouth, around nails, and other body parts.

How do I care for my skin if I am having diabetes?

• Maintain a daily skincare routine
• Keep your skin hydrated
• Reduce the number of baths in winter
• Avoid using hot water baths
• Moisturize your skin
• Use mild soaps
• Observe any changes in your skin
• Check and maintain blood sugar levels

Summary

• Diabetes is a result of a sedentary lifestyle, obesity, and = unhealthy eating habits 
• Itching in diabetics is a common occurrence suggestive of neuropathy (nerve damage)
• Diabetes lowers the body resistance of the patients. Thus, they acquire skin infections
• Maintaining a healthy lifestyle and following instructions from a healthcare provider helps to keep the itch in control
• Keep the skin moisturized
• Avoid hot water baths
• Use humidifiers in winter
• Use anti-itch over-the-counter medication for moisturizing
• Exercise regularly to improve circulation
• Regularly monitor the blood sugar levels to keep them in check
• Maintain a healthy diet