Widespread insulin-dependent juvenile and adult diabetes, as well as the skin alterations that may be caused by this disease, raise the problem of the positive or possibly negative effects of cosmetic treatments.
Since the use of these treatments is so generalized, it is likely to involve a great number of people affected by this illness. Perhaps not all readers know which skin alterations are caused by diabetes, thus a brief introduction may be useful to describe the pathogenetic and clinical characteristics of the most frequent alterations. We must keep in mind that the skin alterations may be caused by several factors. Pathogenesis can be triggered by changes in the carbohydrate metabolism and in other enzymatic activities, by microangiopathy and atherosclerosis, by neuron degeneration, and by the meiopragic condition of the patient's weakened defence mechanisms. The information that is provided for each case will be followed by some hypotheses (1) which are based on the etiopathogenesis of the injury so as to suggest the cosmetic treatment which might have a preventive or palliative effect. One type of skin alteration is characterized by necrobiosis, and in particular, «necrobiosis lipoid diabetorum» which is especially interesting since it quite often appears before diabetes is actually diagnosed. Its multiple, often bilateral lesions are usually located in the pre-tibial area. This alteration mainly affects women, either in the form of small papules, or of extensive, non exfoliating plaques having a yellowish, atrophic centre and bloated margins. The injuries start at the derma level and affect the collagen fibers, which thicken and degenerate. Many authors believe that these alterations are caused by early ageing of the fibroblasts, as often occurs with Pima Indians who are genetically predisposed to diabetes. Collagen produced by these ageing cells has an excessive number of cross-links, and is therefore more resistant to physiologic digestion by collagenase. Due to the slower collagen turnover, we believe that cosmetic preparations containing precursors of this protein, such as Collagenon (2) and Aminoefaderma (3), for instance, are able to penetrate the skin and to stimulate collagen biosynthesis, and may also be helpful in preventing this diabetes-related dermopathy. Another alteration of the skin that is probably correlated to diabetes, and which originates from necrobiotic phenomena of collagen, is disseminated annular granuloma, a typical oval or circular lesion featuring a central part with a hyper or hypo pigmented content and a raised, perhaps erythematous annulus. The diameter of these lesions, which are most often located on the back of the hands and on the arms, may range from a few millimetres up to several centimetres. They are different from «necrosis lipoidica diabetorum» because the skin is not often affected, necrobiotic collagen areas are smaller, and granulomatous infiltrations are usually limited to the upper layers of the derma. It is also interesting to note that some iodine-based treatments may be useful, as reported by some authors. This observation suggests that it may be worth assessing the possible, local effects of some cosmetic preparations containing iodine stable components with derma-affinity, having no enzymotoxic action, but with selectively local, excitatory metabolic action. Iodotrat (4), an organic iodine molecule with an amine structure that is very useful for the topical treatment of cellulite, has these characteristics and may be used for continuous, effective, local treatment. Among the many alterations of the cutis associated with diabetes, the most common one is the appearance of rather small, atrophic, hyper-pigmented lesions on the distal pre-tibial area. These lesions initially appear as small, reddish pimples, which become atrophic within one or two weeks. Under a microscope we can observe that the epidermis has become thinner, the vessel wall in the papillary zone of the derma has thickened, and that both lymphohistiocytic, perivascular infiltrates and hemosiderin deposits are present. The most widespread opinion regarding the etiopathogenesis of these lesions is that they are caused by diabetes-related microangiopathy since they can also be observed in other vessel alterations such as amyloidosis. These lesions seem to be affected by heat and cold, therefore, protecting the skin against excessive temperature variations may be a prophylactic measure in itself. Strong protective action is provided by emulsions containing PME (5), which, unlike other barrier-type protective creams, do not prevent transpiration. Another symptom connected to diabetes-related vessel alterations is a persistent erythema which is often located on the face and neck, though sometimes even on the hands and feet. This symptom is likely caused by the impaired ability of the thickened artery wall to react to physiologic stimuli by vasoconstriction. Patients with this problem should protect themselves against the sun. Therefore, the authors suggest using cosmetic preparations with solar filters which are able to fully prevent – as has been proven for Megasol-complex (6) - both erythema caused by UV-B rays, and phototoxic phenomena caused by UV-A rays without blocking the physiologic pigmentation. True photo dermatitis is what is caused, though quite rarely, by an oral anti-diabetes drug, i.e. chlorpropamide. Even in cases like these, suitable solar filters, such as Megasol-complex, in a proper excipient and dose rate, can be very helpful. Very often diabetes provokes bacterial infections of the cutis (generally caused by staphylococcus aureus, b-hemolytic streptococcus), including various forms of folliculitis, furunculosis, impetigo, erysipelas, and sub-cutis inflammation such as, for example, cellulitis. Other sub-cutis inflammations which are less frequent in the general population, but rather common in diabetic patients, are erythrasma caused by Corynebacterium minutissimum, which is often located in the armpits and between the toes, and Candida-albicans which is responsible for a high percentage of paronychia and dermatophyte cases. When these infections occur, the treatment of choice is systemic administration of antibiotics or chemiotherapeutic agents, but to prevent infection it is of the utmost importance that the patients keep their cutaneous barrier intact. Extremely dry skin, often with fissurations, allows easy access to infectious pathogenic agents. In these cases cosmetic agents which guarantee efficient moisturization, softening, protection, and nourishment of the skin will also help maintain the integrity of the epidermis, [Collagenon (2), Hyaluramine (7), Dermonectin (8)] and if used consistently, represent a useful prophylactic treatment for cutaneous infections. With further reference to the development of micro-organisms, it is worth remembering that the saliva of patients with unbalanced diabetes may have a very high glucose content, which fosters the development of bacterial plaque on the teeth, and of periodontopathies. Therefore, proper oral hygiene is strongly recommended. “Acanthosis nigricans”, which is often associated with resistance to insulin, is characterized by the appearance of hyper pigmented, brown, velvety plaques in the armpits, under the breast, or in the groin. In this case, topical treatment is geared towards “peeling” the altered cutis, which is easily performed by means of a vaseline-based ointment containing 5-10% salicylic acid as the keratolytic agent. Among the alterations of the cutis caused by diabetes and by the accumulation of certain metabolites in this tissue, the following are worth mentioning; xanthomas, in which histologic analysis has revealed the presence of fatty acids and triglycerides; carotenoderma, caused by carotene deposits that diabetics have more difficulty transforming into vitamin A; late cutaneous porphyria, which is characterized by vesicles, blebs, and ulcers in areas that are exposed to light, and which is caused by phototoxic reaction due to an increase in the circulating porphyrin content; hemochromatosis or bronze diabetes, which is characterized by the diabetes-liver cirrhosis –hyper-pigmentation triad, in which epidermal hemosiderin deposits seem to stimulate melanin transfer from melanocytes to keratocytes. Xantomas, carotenoderma, and hemochromatosis are not affected by local treatments. However, in the case of late cutaneous porphyria either avoiding exposure to the sun, or using Megasol-complex based ointments together with kaolin, talc, zinc oxide or titanium dioxide may be beneficial since they prevent photo-activation of porphyrins and the relative formation of free oxygen radicals and lipoperoxides which are harmful to the skin. Some skin disorders of diabetic patients are strongly correlated to the collagen or mucopolysaccharide modifiers of the basic components of the derma. These include “scleroderma”, which must not be mistaken for sclerodermia, whose histologic analysis reveals that the derma is 2 to 3 times thicker than usual, with considerably thickened and more widely spaced collagen fiber bundles. Proper staining allows us to highlight a strong increase in acid mucopolysaccharides, such as hyaluronic acid, which explains the noticeable increase of bonded water that leads to edema. No specific treatment is known, but “restitutio ad integrum” is often spontaneous. Sometimes, the skin may be thickened due to increased glycosylation of derma proteins occurring at the same time as the increase in the cross bonds that stabilize the structure.
To conclude this intentionally brief, and therefore incomplete examination of the cutaneous alterations that may appear in diabetic patients, it must be stressed that their skin is more likely to suffer from skin lesions than the general population. This is the consequence of several factors including altered carbohydrate metabolism, microangiopathy, and neurotrophic disorders that characterize this disease. Of course, the diabetic patient must take care not to expose his skin to soap, detergents, and other agents which can compromise the condition of the skin, thus jeopardizing its barrier function. When using «decorative» cosmetic products, they should only choose the ones that contain no enzymotoxic components.