We know that diabetes is a risk factor for dry eye (Zhang et al, 2016), but did you know that many skin pathologies related to diabetes include dry skin? I did not. The American Academy of Dermatology (2017) lists the following diabetes-related skin disorders:
Necrobiosis Lipoidica Yellow, reddish, or brown patches on the skin that often begin as small raised solid bumps that look like pimples.
Acanthosis Nigricans A dark patch (or band) of velvety skin on the back of the neck, armpit, groin, or elsewhere.
Digital Sclerosis Hard, thickening skin on the hands, fingers, or toes.
Bullosis Diabeticorum A distinct, spontaneous, noninflammatory, blistering condition of acral skin.
Diabetic Dermopathy Brown spots (and sometimes lines) that create a barely noticeable depression in the skin and that form on the shins or other areas of the body.
Eruptive Xanthomatosis Small, reddish-yellow bumps on the buttocks, thighs, crooks of the elbows, or backs of the knees.
Granuloma Annulare Bumps and patches of small lesions that may be skin-colored, red, pink, or bluish purple.
Xanthelasma A sharply demarcated yellowish deposit of fat underneath the skin, usually on or around the eyelids.
Papilloma (Skin Tags) These growths are most common on the eyelids, neck, armpit, and groin.
Xerosis Extremely dry, itchy skin. It is the second most common skin manifestation in people who have diabetes, affecting approximately 44% of diabetics (Goyal et al, 2010).
Cutaneous Lichen Planus Flat-topped, violaceous papulosquamous eruptions on the skin
Vitiligo Patches of the skin lose their pigment.
The frequency of skin lesions in type 2 diabetic patients has been reported in the range of 49% to 84% (Khoharo et al, 2010). In addition, skin and soft tissue infections, both bacterial and fungal, have been reported in up to 30% of diabetics (e.g., Candida albicans can cause angular cheilitis, vulvovaginitis, balanitis, finger web space infection, and paronychia in poorly controlled diabetics) (Khoharo et al, 2010).
The Link Between Diabetes and Skin Pathology
The skin manifestations of diabetes are the result of multiple factors. Abnormal carbohydrate metabolism, other altered metabolic pathways, artherosclerosis, microangiopathy, neuron degeneration, and impaired host mechanisms all play a role (Ronald and Ricky, 1984). Skin of diabetic patients has increased capillary fragility, and blood vessels show decreased circulation. Other pathogenic mechanisms in diabetic persons include a hyperglycemic environment, increasing the virulence of some pathogens; lower production of interleukins in response to infection; reduced chemotaxis and phagocytic activity, and immobilization of polymorphonuclear leukocytes (Casqueiro et al, 2012). Similarly, patients who have diabetic lymphedema have leakage of lymphatic fluid into the tissue, causing swelling and connective tissue damage and increased risk of infection. While diabetes generally causes damage to the arteries and capillaries, lymphedema is the result of damage to the lymphatic system. Together, these changes damage the arterial and lymphatic systems and lead to damage of the subcutaneous tissue, connective tissue, and skin, resulting in increased swelling, decreased levels of oxygen in the skin and connective tissue, and susceptibility to infection.
I usually ask my patients about any skin conditions that they may have, generally looking for an allergy/atopy connection. I now have another reason to ask. Consider adding this probing query to your clinical history not only as a clue to your dry eye diagnosis, but also as a clue to undiagnosed diabetic disease. CLS
For references, please visit www.clspectrum.com/references and click on document #268.