Signs of Diabetes on Skin

Diabetes can affect any part of the body and skin is one of them. Around 60% of diabetic patients have some kind of skin problem. Unfortunately, the majority of patients present quite late and by then, their symptoms will have worsened. In some patients, the manifestation of a skin disorder is the first sign in diagnosing diabetes. Skin conditions may also heal slowly if the patient’s blood glucose is not under control.

The underlying mechanisms for skin problems include raised blood glucose and glucose end products, blockage in the small blood vessels, nerve damage and low immunity of the patient.

Skin Infections:

These can occur in non-diabetic people too, but are more commonly seen in patients with diabetes. These could be bacterial, fungal, or less commonly, viral.

Bacterial Infections:

Usually caused by the Staphylococcus organism.  Commonly seen conditions are:

• Furuncle/Boil: a deep infection of the hair follicle and the surrounding tissue which causes a red, tender, pus filled lump.
• Folliculitis: a superficial infection of multiple hair follicles which are pus filled and much smaller than a boil.
• Carbuncle: a collection of several boils.Scarring is likely on healing.
• Sty: an infection causing a tender lump on the eye lid.
• Other severe infections include cellulitis (infection of the skin), osteomyelitis (Infection of the bone) etc. These infections may be caused by trivial wounds.

 Fungal Infections:

Usually caused by Candida species. This results in an itchy, red, moist rash surrounded by faint scales. It is common in warm, sweaty areas like skin folds of the neck, the groin, arm pits, between fingers and toes, underneath breasts, vagina, and around the outer genital areas of both males and females.

Skin Conditions Associated With Diabetes:

These are specific to diabetes.

Necrobiosis Lipoidica Diabeticorum:

This is a slightly raised,irregular shaped patch with red borders and a shiny yellowish centre that has small visible blood vessels. The centre of the patch breaks easily due to the presence of thin skin leading to ulcer formation, which can then become infected. Scarring is quite common. They start as small discrete patches and then join together. They are most commonly present on the shins.

Diabetic Dermopathy:

Also known as Pigmented tibial patches or shin spots, as they are present on the shins. They start as small red lumps, and over one to two weeks, undergo tissue breakdown, thus forming small, irregularly oval or circular shallow lesions.

Diabetic Bullae:

These are single or multiple fluid filled blisters, ranging in size from half a centimetre to several centimetres. They occur spontaneously, are painless, and are commonly found on the fingers, toes, hands, feet, lower legs and arms.

Diabetic Thick Skin:

The skin of diabetic patients is thicker than normal people. The skin also has loss of elasticity. This is related to nerve damage and an increased duration of poorly controlled diabetes.

• Patients with advanced skin thickness may have diabetic hand syndrome. Here there is thickening of the skin at the finger joints. This is called sclerodactly and results in painful stiff fingers.
• Dupuytrens Contracture: This is a hand deformity that causes the fingers to bend into the palm; usually the ring finger and little finger are affected. It develops over several years.There is a thickening of the tissue beneath the skin of the palm and thick knots of tissue form, causing a thick cord that bends the fingers.

Scleroderma Diabeticorum:

Seen commonly in the nape of the neck, upper chest, back and arms of obese diabetic patients.There is diffuse thickening of the skin and skin markings are lost. The thickened skin forms pits when forceful pressure is applied for 30 sec. Usually patients do not have any symptoms, though some back pain, neck pain and limitation of movement of the affected area has been reported.

Acanthosis Nigricans:

This is a velvety, black or greyish pigmented thick patch, seen commonly in obese diabetic patients. It is usually present in body folds like the neck, under the breasts, the groin, arm pits etc. This is due to insulin resistance.

Eruptive Xanthoma:

This is caused by raised triglyceride and low density lipoprotein cholesterol levels. They present as small yellow lesions of about 0.5 cm in diameter, mainly on the knees, legs and buttocks. They occur in crops and grow rapidly, settling down once the triglyceride levels reduce.

Granuloma Annulare:

This characteristic lesion consists of small pink or skin coloured lumps arranged in a circular or oval shape. They are commonly seen over the bony prominences of the forearm and legs.

Miscellaneous conditions:

These are more commonly seen in diabetic patients, though not specific to them.

• Skin Tags:These are small fleshy skin lesions, mostly seen on the neck, eyelids and arm pits.
• Vitiligo: These are depigmented skin patches on the body. Affected parts appear lighter than the rest of body due to loss of pigment producing cells.
• Psoriasis: A skin condition with reddish patches and scales that can be itchy. This is due to rapid turnover of the skin cells.
• Xerosis/Dry skin: This is characterised by persistent itching and cracks in the skin. Breakage of skin leads to skin infections. Xerosis also delays wound healing.
• Eczema/Dermatitis: Here the skin gets inflamed and results in sore, red, dry and cracked skin which is itchy.
• Pruritus/ Itching: This could be due to dry skin, a fungal infection or poor circulation which is seen in diabetes patients.

Iatrogenic Skin Conditions:

These are caused by anti-diabetic drugs taken by the patient.

Insulin reactions:

• Lipoatrophy: This occurs at insulin injection sites, usually seen with longer acting insulins. There is a loss of localised fat tissue and can cause cosmetic disfigurement.
• Lipohypertrophy: Here, there is accumulation of fat under the skin leading to soft, fatty lumps. This is also seen at insulin injection sites.
• Insulin Allergy: Quite rare with analogue insulins. Typically the rash is red, itchy, raised and swollen

Sulphonylureas:

Normally occurs within two months of taking the drug. The skin lesion is comprised of generalised redness with itching, a reddish patch or a raised, swollen, pale red lesion.

References:

• Necrobiosis Lipoidica. Lowitt MH, Dover JS, Journal of American Academy of Dermatology, 1991; 25:735-748
• Cutaneous manifestations of Diabetes Mellitus. Jelinek JE, International Journal of Dermatology, 1994; 33:605-617
• Localized skin reactions to insulin: insulin lipodystrophies and skin reactions to pumped subcutaneous insulin therapy. Levandoski LA, White NH, Santiago JV, Diabetes Care, 1982;5:6-10