The skin frequently serves as a marker for underlying internal disease. The type of lesion typically relates to a specific disease or type of disease.
(See also Evaluation of the Dermatologic Patient Evaluation of the Dermatologic Patient History and physical examination are adequate for diagnosing many skin lesions. Some require biopsy or other testing. Important information to obtain from history includes Personal or family... read more .)
Patients with dermatomyositis Autoimmune Myositis Autoimmune myositis is characterized by inflammatory and degenerative changes in the muscles (polymyositis, necrotizing immune-mediated myopathy) or in the skin and muscles (dermatomyositis)... read more who are over age 40 have an increased risk of breast, lung, ovarian, and gastrointestinal cancers.
Acute onset of multiple seborrheic keratoses Seborrheic Keratoses Seborrheic keratoses are superficial, often pigmented, epithelial lesions that are usually warty but may occur as smooth papules. The cause of seborrheic keratosis is unknown, but genetic mutations... read more (Leser-Trélat sign) may indicate underlying internal cancer, particularly adenocarcinoma. However, because of the high prevalence of seborrheic keratoses in healthy adults, this sign may be overdiagnosed.
Acute febrile neutrophilic dermatosis Acute Febrile Neutrophilic Dermatosis Acute febrile neutrophilic dermatosis is characterized by tender, indurated, dark-red papules and plaques with prominent edema in the upper dermis and dense infiltrate of neutrophils. The cause... read more (Sweet syndrome) is sometimes associated with hematologic cancer.
Acanthosis nigricans that is associated with cancer can be of rapid onset and particularly widespread. Acquired ichthyosis or pruritus without a clearly associated dermatitis may indicate occult cancer, often lymphoma.
Paraneoplastic pemphigus is a relatively rare autoimmune blistering disease that has been associated with various cancers, including leukemias.
Carcinoid syndrome Carcinoid Syndrome Carcinoid syndrome develops in some people with carcinoid tumors and is characterized by cutaneous flushing, abdominal cramps, and diarrhea. Right-sided valvular heart disease may develop after... read more (flushing and erythema of the neck) is associated with carcinoid tumor.
Erythema gyratum repens is a rare eruption consisting of concentric erythematous lesions, resembling wood grain, which has been associated with various cancers.
Many skin findings are associated with endocrinopathies but are not specific.
Patients with diabetes mellitus may have acanthosis nigricans, necrobiosis lipoidica, perforating disorders, and scleredema (hard, thick skin, typically on the upper back, neck, and shoulders).
Thyroid disease, both hypothyroidism Hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis... read more and hyperthyroidism Hyperthyroidism Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms include palpitations, fatigue, weight loss, heat intolerance, anxiety, and tremor... read more , can affect hair, nails, and skin.
Cushing syndrome Cushing Syndrome Cushing syndrome is a constellation of clinical abnormalities caused by chronic high blood levels of cortisol or related corticosteroids. Cushing disease is Cushing syndrome that results from... read more causes striae distensae, moon facies, and skin fragility.
Addison disease Addison Disease Addison disease is an insidious, usually progressive hypofunctioning of the adrenal cortex. It causes various symptoms, including hypotension and hyperpigmentation, and can lead to adrenal crisis... read more is characterized by hyperpigmentation that is accentuated in skin creases and areas of trauma.
Gastrointestinal (GI) disorders
Skin conditions commonly associated with GI disorders include
Lichen planus Lichen Planus Lichen planus is a recurrent, pruritic, inflammatory eruption characterized by small, discrete, polygonal, flat-topped, violaceous papules that may coalesce into rough scaly plaques, often accompanied... read more and porphyria cutanea tarda Porphyria Cutanea Tarda Porphyria cutanea tarda (PCT) is a comparatively common hepatic porphyria affecting mainly the skin. Liver disease is also common. PCT is due to an acquired or inherited deficiency in the activity... read more : Hepatitis C infection
Diffuse hyperpigmentation in patients with diabetes (known as bronze diabetes): Hemochromatosis
Erythema nodosum Erythema Nodosum Erythema nodosum is a specific form of panniculitis characterized by tender, red or violet, palpable, subcutaneous nodules on the shins and occasionally other locations. It often occurs with... read more : Inflammatory bowel disease, sarcoidosis, and various infections