Hyperpigmentation - A Sign of Systemic Disease - Skin Disorders

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Elevated pigmentation of the skin is seen in a number of systemic diseases. In porphyria cutanea tarda, hyperpigmentation occurs on the face and arms, presumably simply because of the photosensitizing impact of porphyrins. It is accompanied by hirsutism of the face together with skin fragility or blistering of the dorsal hands. There commonly is laboratory evidence of liver disease. Elevated urine levels of uroporphyrin and coproporphyrin are diagnostic. When skin lesions suggestive of porphyria cutanea tarda are accompanied by gastrointestinal symptoms, neurologic difficulties, or psychiatric changes, stool porphyrins need to be obtained to evaluate for the attainable presence of variegate porphyria.

In Addison's disease, hyperpigmentation occurs over the entire body, but there is accentuation of the brown color in old scars and in skin creases. The nail beds and the oral mucosa could also turn into hyperpigmented. Hyperpigmentationin Addison's disease is due to increased output of pituitary hormones such as melanocyte-stimulating hormone (MSH) and adrenocorticotropic hormone (ACTH), each of which are capable of stimulating pigment production. Low semm cortisol levels are present, and the diagnosis is established by the failure of cortisol levels to rise following appropriate adrenal stimulation. In patients whose Addison's illness occurs as component of a multiglandular deficiency syndrome, vitiligo may perhaps also be present.

In scleroderma, hyperpigmentation is generalized, but there is accentuation of the brown color on the dorsal surface of the arms and hands. Occasionally, vitiligo-like mantles of hypopigmentation will be interspersed within areas of darkened skin. The mechanism for the pigmentation is unknown. Diagnosis is supported by the concomitant presence of Raynaud's phenomenon, sclerodactyly, decreased esophageal motility, and, in advanced cases, pulmonary, cardiac, and renal disease. Skin biopsy, to identify the degree of sclerosis, helps to confirm a clinical diagnosis.

The generalized hyperpigmentation of hemochromatosis is additional slate colored or bronze than brown. Jaundice may well also be present. The mucous membranes turn out to be hyperpigmented in 20% of patients. The pathogenesis of the pigmentation is unknown. Glucose abnormalities are present, and the diagnosis is confirmed by liver biopsy, which on proper staining demonstrates elevated levels of hepatic iron.

Hyperpigmentation related with malignants is most classically found with carcinoma of the lung. The pigmentation occurs mainly because of the MSH-like activity of polypeptides elaborated by such tumors. Generalized melanosis may possibly also be seen with advanced, widespread melanoma, in which case the color is due to the direct production of pigmented compounds by the malignant cells.

The pigmentation in acanthosis nigricans, although generalized, is most notable in intertriginous locations exactly where it is accompanied by the presence of densely pigmented, soft velvety ridges. These adjustments are especially accentuated on the side of the neck, in the axillae, and in the groin. Elevated pigmentation of mucosal surfaces is also sometimes present. The mechanism responsible for the pigmentation is unknown, but elevated MSH output is suspected. Acanthosis nigricans is most typically discovered as an unimportant aspect of obesity, but its occurrence in youngsters and adults of regular weight need to raise a question of associated malignancy. Central nervous system tumors are most generally the trigger of acanthosis nigricans in children, whereas gastrointestinal tumors are commonly identified in adults with this condition.

Most patients with severe neurofibromatosis show some evidence of generalized hyperpigmentation in addition to the presence of cafe-au-lait patches .

Diffuse hyperpigmentation from time to time occurs as a result of chemotherapeutic agents administered to patients with varying kinds of malignancy. In such scenarios, pigmented bands on the nails might possibly also be noted.