Cutaneous Manifestations of Internal Disease

CUTANEOUS MANIFESTATIONS OF DIABETES MELLITUS Approximately 30% of patients with diabetes mellitus develop a skin disorder sometime during the course of disease. • Candida infections (mouth, genital) • Carotenodermia (yellow skin) • Diabetic bullae • Diabetic dermopathy (shin spots) • Diabetic thick skin • Erythema (face, lower legs, feet) • External otitis • Finger pebbles • Foot ulcers • Acanthosis nigricans (insulin resistance syndromes) • Gas gangrene (nonclostridial) • Granuloma annulare (localized or generalized) • Insulin lipodystrophy • Necrobiosis lipoidica • Yellow nails • Perforating disorders • Eruptive xanthomas

Diabetic Dermopathy This is the most common cutaneous marker of diabetes and occurs in 40% of diabetics. There is an unfavourable association with the three most common microangiopathic complications of diabetes: neuropathy, nephropathy and retinopathy. There is also an association with coronary artery disease. Clinically: Asymptomatic, round, atrophic, hyperpigmented areas on shins (shin spots). They begin as round-to-oval, flat topped, red, scaly papules that may become eroded. They eventually clear or heal with atrophy and hyperpigmentation. Shin spots may also occur on forearms, anterior lower thighs, and sides of feet. Men are affected twice as often as women. May be initiated by trauma.

Diabetic Bullae (Bullosis Diabeticorum) Etiology is unknown but may be ischemic. Crops of bullae appear abruptly in diabetics, usually on feet and lower legs but may occur on arms. Usually develop overnight without preceding trauma. There is little pain or discomfort. They arise on nonerythematous base and are usually multiple, variable in size, and occasionally huge. They are tense, and spontaneously rupture in 1 week leaving a painless ulcer (that is difficult to heal) with firmly adherent crust. Recurrences may occur. Rx?

Necrobiosis Lipoidica Necrobiosis lipoidica (NL) is a disease of unknown origin, but more than 50% of the patients with NL are insulin dependent. However, it is seen in less than 1% of the entire diabetic population. The average age is 30 years. Mostly lesions are confined to the anterior lower legs. Clinically: The eruption begins as an oval, violaceous patch that expands slowly. The advancing border is red, and the central area turns yellow-brown then atrophies and exhibits a waxy surface; telangiectasias are present. Ulceration occurs, particularly following trauma. Rx: Topical, intralesional and systemic steroids; pentoxifylline; aspirin and dipyridamole; cyclosporine; tacrolimus ointment; etanercept; and skin grafting.

Granuloma Annulare (GA) The association of GA with diabetes is not documented but in one study, 12% of patients with GA had diabetes. The disease begins with an asymptomatic, flesh-colored or red papule that undergoes central involution. Over months, a ring of papules slowly increases in diameter to 0.5 - 5 cm. The localized form is the most common, it is seen in young adult females and usually found on the lateral or dorsal surfaces of the hands and feet.

The duration of the disease is highly variable. No scarring after resolution. Patients who develop GA usually heal, remain healthy, and do not usually develop other odd diseases. The familial occurrence of GA is uncommon but has been noted. Rx: Localized lesions are asymptomatic and are best left untreated. Intralesional triamcinolone acetonide injected only into the elevated border. Also, topical steroids, and imiquimod cream.

ACANTHOSIS NIGRICANS Acanthosis nigricans (AN) is a nonspecific reaction pattern that may accompany obesity; diabetes; excess corticosteroids; pineal tumors; endocrine disorders (insulin resistance plus hyperinsulinemia); several genetic variants; drugs such as nicotinic acid, estrogens, and corticosteroids; and adenocarcinoma. AN is classified into malignant (mostly gastric cancer) and benign (obesity, hereditary and endocrine) forms. In all cases the disease presents with symmetric, brown thickening of the skin. In time the skin may become quite thickened as the lesion develops a leathery, warty, or papillomatous surface. The most common site of involvement is the axilla, but also flexural areas of the posterior neck, groin, belt line, dorsal surfaces of the fingers, mouth, and around the areolae of the breasts and umbilicus. Rx: No treatment. A 12% ammonium lactate or Retin-A cream.

XANTHOMAS AND DYSLIPOPROTEINEMIA Xanthomas are lipid deposits in the skin and tendons that occur secondary to a lipid abnormality. These localized deposits are yellow and are frequently very firm. Xanthelasma and plane xanthomas Plane xanthomas occur in several areas of the body (palms) and are flat or slightly elevated. Xanthelasma is the most common form. About 50% of the patients with xanthelasma have normal cholesterol levels. However, patients with xanthelasma should be considered to have an increased risk of cardiovascular disease independent to the level of plasma lipids as there is increased risk for atherosclerosis. Rx: Trichloroacetic acid (TCA).

ERUPTIVE XANTHOMAS These are yellow, 1- to 4-mm papules with a red halo around the base. They appear suddenly in crops on extensor surfaces of the arms, legs, and buttocks and over pressure points. Pruritus is common. Lesions clear rapidly when serum lipid levels are lowered. They are a sign of hypertriglyceridemia and appear in secondary hyperlipidemias (e.g., diabetes).

TUBEROUS XANTHOMAS These are slowly evolving yellow papules, nodules, or tumors that occur on the knees, elbows, and extensor surfaces of the body and the palms. TENDINOUS XANTHOMAS These smooth, deeply situated nodules are attached to tendons, ligaments, and fascia. They are most often found on Achilles tendons and the dorsal aspects of the fingers.