Addison disease is rare with an estimated annual incidence of 0.8 cases per 100,000 of the population in Western societies. It is due to bilateral destruction of the adrenal cortex. Formerly, the most common cause was tuberculosis. Most cases now are due to organ-specific auto-immune destruction and opportunistic infections such as histoplasmosis in patients with AIDS. Due to this, it is likely that the number of patients with Addi-son disease will increase significantly. Addison disease may be associated with autoimmune polyglandular deficiency type I (Addison disease, chronic mucocutaneous candidosis, hypoparathyroidism) and autoimmune polyglandular deficiency type II (Addison disease, primary hypothyroidism, primary hypogonadism, insulin-dependent diabetes, pernicious anaemia, vitiligo) .
Clinically, there is usually slowly progressive weakness, lassitude and weight loss. Gastro-intestinal symptoms can include diarrhoea or constipation and anorexia, nausea and vomiting. Postural hypotension is a common symptom. An early sign is pigmentation of the skin and oral mucosa secondary to increased adrenocortico-
tropic hormone (ACTH) secretion. Parts of the skin exposed to the sun and areas subjected to trauma or friction become bronzed . There is also increased pigmentation in skin folds and scars. About 10% of patients also show areas of vitiligo.
Oral pigmentation is variable and where present ranges from light brown to densely black . The gingiva, lateral margins of the tongue, buccal mucosa and lips are the sites of predilection. Microscopy of the areas shows increased melanin predominantly in the basal keratinocytes.
Peutz Jeghers syndrome (periorifacial lentiginosis) comprises melanotic spots of the face, mouth and less commonly the hands and feet, together with intestinal polyposis. It is inherited as an autosomal dominant trait with nearly complete penetrance , but new mutations occur in 40% of cases.
There are multiple ephelides on the face and mela-notic macules in the mouth involving the lower labial and buccal mucosa in particular. Lesions are often present at birth. The facial pigmentation is around the mouth, nose and eyes and tends to progressively fade after puberty. The mucosal pigmentation persists into adult life.
There are hamartomatous polyps throughout the intestinal tract, but typically these are most numerous in the small intestine. They can give rise to abdominal pain and bleeding and intussusception is a rare complication. The polyps have a low malignant potential, with those in the colon having the highest risk. Patients also are at increased risk of malignancy at other sites including the uterus, ovary, pancreas and breast.
Racial pigmentation is the most common cause of intraoral pigmentation. It is seen predominantly in Blacks, Asians and people of Mediterranean origin, but about 5% of Caucasians also have significant intraoral pigmentation. The degree and extent of racial pigmentation is very variable and does not necessarily correlate with the depth of skin pigmentation. It can vary from light brown to almost black and the most commonly involved sites are the gingiva, palate and buccal mucosa. Sometimes when the tongue is involved the only areas affected are the fungiform papillae, producing an appearance of spotty pigmentation.
Microscopy shows increased melanocytic pigmentation of the basal and, to a much lesser degree, the immediately suprabasal keratinocytes. The denser pigmenta tion is due to increased synthesis of melanin by melanocytes, which are otherwise normal in number and distribution.
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