Treatment of porphyria of the skin generally involves the avoidance of sunlight, while treatment for acute porphyria may involve giving intravenous heme or a glucose solution. Rarely, a liver transplant may be carried out.The precise prevalence of porphyria is unclear, but it is estimated to affect between 1 and 100 per 50,000 people. Rates are different around the world. Porphyria cutanea tarda is believed to be the most common type. The disease was described as early as 370 BC by Hippocrates. The underlying mechanism was first described by German physiologist and chemist Felix Hoppe-Seyler in 1871. The name porphyria is from the Greek πορφύρα, porphyra, meaning "purple", a reference to the color of the urine that may be present during an attack. Signs and symptoms
Acute porphyrias
Acute intermittent porphyria (AIP), variegate porphyria (VP), aminolevulinic acid dehydratase deficiency porphyria (ALAD) and hereditary coproporphyria (HCP). These diseases primarily affect the nervous system, resulting in episodic crises known as acute attacks. The major symptom of an acute attack is abdominal pain, often accompanied by vomiting, hypertension (elevated blood pressure), and tachycardia (an abnormally rapid heart rate).The most severe episodes may involve neurological complications: typically motor neuropathy (severe dysfunction of the peripheral nerves that innervate muscle), which leads to muscle weakness and potentially to quadriplegia (paralysis of all four limbs) and central nervous system symptoms such as seizures and coma. Occasionally, there may be short-lived psychiatric symptoms such as anxiety, confusion, hallucinations, and, very rarely, overt psychosis.
In weeks to a month times the lesions begin to clear and disappear (with prednisone) leaving behind areas of retinal pigment epithelial atrophy and diffuse fine pigmentation (scarring). Rarely choroidal neovascularization occur as a late onset complication. Cause
Since The cause of the inflammation remains unknown, with various theories of it occurring as an autoimmune response to a mild infection, or the possibility of it being viral because of the preceding flu-like illness that generally accompanies it. It is usually associated with HLA-B7 and HLA-DR2. The underlying etiology of APMPPE continues to cause debate. The term Pigment Epitheliopathy was chosen by Gass to reflect what he thought was the tissue most significantly affected. Van Buskirk et al., and Deutman et al. proposed choriocapillaris ischemia as the more likely primary etiology. Indocyanine green angiography (ICGA), and OCT angiography (OCTA) studies have provided support for choriocapillaris involvement. However, a novel hypothesis has recently been proposed implicating a direct neurotropic infection as a possible underlying cause given the dynamic changes observed along the neuronal pathway of the retina

Diagnosis
Diagnosis is usually made on clinical appearance alone on fundoscopy and/or retinal imaging. Supplementary tests such as Optical coherence tomography(OCT) and fundus fluorescein angiography/Indocyanine angiography together with OCT-Angiography are commonly performed to help aid diagnosis and monitoring. Treatment
Owing to the self-limiting nature of the disease, treatment is generally not required. In cases where lesions appear to be interfering with the optic nerve, methyl prednisone is prescribed. Prognosis
Vision improves in almost all cases.