diabetes and vascular disease

Photoessay: The Skin and Diabetes Mellitus

by A Huntley

Dermatology Online Journal, December 1995
Volume 1, Number 2

Microvascualar Disease

periungual erythema

nailfold capillaries

dermopathy

pigmented purpura

additional images of dermopathy and purpura

periungual erythema

Microvascular disease is a major complication of diabetes mellitus. At the capillary level, this can be due to both a structural (e.g. thickened capillary wall) and functional problems (increased blood viscosity). Impaired blood flow due to increased viscosity results in dilated capillary loops, and such clinical manifestations as facial blush and periungual erythema.

Fig 21. Finger of a patient with diabetes mellitus demonstrating erythema of the proximal nail fold. This erythema is associated with dilatation of the superficial vascular plexus.

nailfold capillaries

A study was initiated to examine the capillary loops of the proximal nail folds of the toes in insulin dependent diabetics. Most of the patients had periungual erythema which was due to be engorgement of the capillary loops. Because the capillary loops of that portion of the proximal nail fold which extends over the surface of the nail are oriented horizontal to the skin surface, more vessel area can be visualized at the surface.

Fig 22. Microscopic view of hallux proximal nail fold of a patient with diabetes mellitus, demonstrating engorgement of the capillary loops. The photograph was taken with a 40x dissecting microscope after the surface was rendered more transparent by coating with oil. This type of capillary vascular engorgement was common among the diabetics with poor metabolic control.

dermopathy

Diabetic dermopathy is a condition characterized by the presence of multiple hyperpigmented atrophic macules on the legs. Typical lesions are depressed (atrophic) and appear to have post-inflammatory hyperpigmentation. These lesions have been classified with vascular disorders because histology sections may demonstrate red blood cell extravasation and capillary basement membrane thickening. Patients can usually relate antecedent trauma or inflammation and sometimes precipitating lesions coexist with the atrophic ones.

Fig 23. Shin of a patient with diabetes mellitus demonstrating hyperpigmented atrophic macules. The patient relates previous trauma for each of these spots. The lesion on the left demonstrates evolution from the traumatic to the atrophic hyperpigmented phase.

One or two hyperpigmented atrophic macules are occasionally encountered on the legs of non-diabetic patients, but these lesions are much more common in diabetics. The occurrence of 4 or more such lesions is almost always limited to persons with diabetes, and correlates well with the presence of retinopathy.

Figs 24,25. Legs of two patients with diabetes mellitus. The patient on the left is a teenage girl with insulin dependent diabetes. The patient on the right is an adult onset diabetic. Both have multiple atrophic hyperpigmented macules, so-called diabetic dermopathy.

Figs 26,27. Close-up views of the atrophic hyperpigmented macules on the shins of two diabetic patients.

Inspection of individual lesions simply demonstrates atrophic hyperpigmented macules, occasionally with some of the preceding lesion. On the basis of clinical observation, diabetic dermopathy would appear to be consistent with focal extravasation, impaired wound healing and postinflammatory hyperpigmentation.

pigmented purpura

Known as a common phenomenon of aging, pigmented purpura of the legs is most often encountered in the elderly diabetic population. These areas of spontaneous focal extravasation from the microcirculation are recognized as brown to red macules and patches. Pigmented purpura often coexists with diabetic dermopathy.

Figs 28,29. Two elderly patients with diabetes mellitus demonstrating erythematous, brown, and golden macular changes on the shins. The small erythematous areas, representing recent vascular hemorrhage gradually enlarge, turn brown, and coalesce with neighboring lesions. With resolution, the remaining lesion have a golden appearance.

Fig 30. Close-up view of the shin of a diabetic patient demonstrating the presence of diabetic dermopathy and pigmented purpura. The dermopathy is distinguished by the atrophy whereas the changes involved with pigmented purpura are macular.