rifampicin, phenytoin). Adrenal destruction
Autoimmune adrenalitis is the most common cause of Addisons disease in the industrialised world. Autoimmune destruction of the adrenal cortex is caused by an immune reaction against the enzyme 21-hydroxylase (a phenomenon first described in 1992). This may be isolated or in the context of autoimmune polyendocrine syndrome (APS type 1 or 2), in which other hormone-producing organs, such as the thyroid and pancreas, may also be affected.Adrenal destruction is also a feature of adrenoleukodystrophy (ALD), and when the adrenal glands are involved in metastasis (seeding of cancer cells from elsewhere in the body, especially lung), hemorrhage (e.g. in Waterhouse–Friderichsen syndrome or antiphospholipid syndrome), particular infections (tuberculosis, histoplasmosis, coccidioidomycosis), or the deposition of abnormal protein in amyloidosis. Pathophysiology
Hyponatremia can be caused by glucocorticoid deficiency. Low levels of glucocorticoids leads to systemic hypotension (one of the effects of cortisol is to increase peripheral resistance), which results in a decrease in stretch of the arterial baroreceptors of the carotid sinus and the aortic arch. This removes the tonic vagal and glossopharyngeal inhibition on the central release of ADH: high levels of ADH will ensue, which will subsequently lead to increase in water retention and hyponatremia.Differently from mineralocorticoid deficiency, glucocorticoid deficiency does not cause a negative sodium balance (in fact a positive sodium balance may occur).
Acute cutaneous lupus erythematosus is a cutaneous condition characterized by a bilateral malar rash (also known as a "butterfly rash") and lesions that tend to be transient, and that follow sun exposure. The acute form is distinct from chronic and subacute cutaneous lupus erythematosus, which may have different types of skin lesions. Cutaneous lupus erythematosus is associated with both lupus erythematosus-specific lesions and cutaneous manifestations that are not specific to lupus erythematosus, such as oral ulcers and urticaria. Because of the diagnostic criteria used to diagnose systemic lupus erythematosus, a patient with only cutaneous manifestations may be diagnosed with the systemic form of the disease. Forms
Acute cutaneous lupus erythematosus can be either localized or generalized. Localized form
The localized form of the disease is most commonly associated with the malar rash and normally develops in a patients twenties. The localized form occurs only above the patients neck and is not associated with rashes in other parts of the body. Generalized form
Generalized acute cutaneous lupus erythematosus includes skin below the patients neck and is described as a macropapular rash or photosensitive lupus dermatitis. Symptoms include similar erythematic lesions as seen in the localized form, but forms a symmetrical rash and can be mistaken for a drug rash. See also
Lupus erythematosus
List of cutaneous conditions


== References ==