Polymorphous light eruption (PLE), sometimes also called polymorphic light eruption (PMLE), is a non-life-threatening and potentially distressing skin condition that is triggered by sunlight and artificial UV exposure in a genetically susceptible person, particularly in temperate climates during the spring and early summer. Due to its many clinical appearances, it is named polymorphic or polymorphous and the terms are used interchangeably. The resulting itch can cause significant suffering.PLE is also defined as an idiopathic primary photodermatosis, in which the photosensitizer is unknown.Treatments include prevention with sun avoidance and supervised light therapy, and symptom control with topical steroids. Signs and symptoms
Typically, the first episode develops in the spring following the first exposure to intense sun. Further episodes of the irritable rash occur several hours to days following subsequent sun exposure.PLE appears on areas of the skin newly exposed to sunlight such as the visible part of the neckline, backs of hands, arms and legs, and feet, but less commonly the face. At these areas, there may be feelings of burning and severe itching. Smooth red-topped small papules which merge into plaques, small fluid-filled blisters (papulovesicles) and less commonly target-shaped lesions which look like erythema multiforme may be visible.
Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of kidney function, (usually a 50% decline in the glomerular filtration rate (GFR) within 3 months) with glomerular crescent formation seen in at least 50% or 75% of glomeruli seen on kidney biopsies. If left untreated, it rapidly progresses into acute kidney failure and death within months. In 50% of cases, RPGN is associated with an underlying disease such as Goodpasture syndrome, systemic lupus erythematosus or granulomatosis with polyangiitis; the remaining cases are idiopathic. Regardless of the underlying cause, RPGN involves severe injury to the kidneys glomeruli, with many of the glomeruli containing characteristic glomerular crescents (crescent-shaped scars). Signs and symptoms
Most types of RPGN are characterized by severe and rapid loss of kidney function with marked hematuria; red blood cell casts in the urine; and proteinuria sometimes exceeding three grams in twenty-four hours, a range associated with nephrotic syndrome. Some patients also experience hypertension and edema. Severe disease is characterized by pronounced oliguria or anuria, which portends a poor prognosis. Pathophysiology
It is thought that antineutrophil cytoplasmic antibodies (ANCA) interact with antigens in the cytoplasm of neutrophils to cause an early degranulation, triggering the release of lytic enzymes at the site of injury and leading to the formation of glomerular crescents that consist primarily of parietal epithelial cells from Bowmans capsule and in some cases podocytes. Diagnosis
Serum analysis often aids in the diagnosis of a specific underlying disease.