Pigmentosa

Pigmentosa is a medical term derived from Latin pigmentosus ("pigmented") used to describe diseases or conditions in which abnormal pigmentation is a defining feature. It is not the name of a single disorder, but an attributive term that appears in various compound disease names.

In ophthalmology, the best-known usage is retinitis pigmentosa (RP), an inherited retinal dystrophy group characterized by progressive peripheral vision loss and night blindness, along with pigmentary changes in the retina due to degeneration of photoreceptors and retinal pigment epithelium.

In dermatology, pigmentary disorders involve abnormal skin pigmentation; however, pigmentosa is not typically used as an isolated diagnosis and is more often encountered in descriptive or historical contexts about pigmented skin conditions.

Genetics: RP shows genetic heterogeneity, with many genes and inheritance patterns including autosomal dominant, autosomal recessive, and X-linked.

Diagnosis: based on eye examination, visual field testing, electroretinography, and genetic testing; imaging with optical coherence tomography can show retinal layer changes.

Management and prognosis: there is no cure for RP; management emphasizes maximizing remaining vision, low-vision aids, safety, and genetic counseling. Some gene therapies exist for specific subtypes, and prognosis varies by genotype.

See also: Retinitis pigmentosa; retinal dystrophy; pigmentary disorders.