Phototoxins are toxins that can cause allergic reactions in particularly susceptible individuals and which can cause dangerous photosensitivity in a much broader range of subjects. This article or section does not cite any references or sources. ... Photosensitivity is the amount to which an object reacts upon receiving photons of light. ...

Phototoxins are common in:

• a variety of plants (including food plants where they may be a biological defence):
  • many citruses contain essential oils that are photosensitisers;
  • some homeopathic remedies (notably St John's wort, though incident rates for this plant are reportedly low);

• some prescribed medications (such as tetracycline antibiotics); and
• many essential oils, perfumes and cosmetics.

Ingested medications may cause systemic photosensitivity and topically applied medications, cosmetics and essential oils may lead to local (or perhaps systemic) photosenstivity. Curiously and ironically, para-aminobenzoic acid (PABA) found in some sunscreens can also cause photosensitivity. Species & major hybrids Species Citrus aurantifolia - Key lime Citrus maxima - Pomelo Citrus medica - Citron Citrus reticulata - Mandarin & Tangerine Major hybrids Citrus ×sinensis - Sweet Orange Citrus ×aurantium - Bitter Orange Citrus ×paradisi - Grapefruit Citrus ×limon - Lemon Citrus ×limonia - Rangpur lime Citrus ×latifolia - Persian lime See also main text for other hybrids Citrus... An essential oil is a concentrated, hydrophobic liquid containing volatile aromatic compounds from plants. ... It has been suggested that Veterinary homeopathy be merged into this article or section. ... Binomial name Hypericum perforatum L. St Johns wort (IPA pronunciation: , rhyming with hurt, or ) used alone refers to the species Hypericum perforatum, also known as Klamath weed or Goat weed, but, with qualifiers, is used to refer to any species of the genus Hypericum. ... Tetracycline (INN) (IPA: ) is a broad-spectrum antibiotic produced by the streptomyces bacterium, indicated for use against many bacterial infections. ... An essential oil, is a concentrated, hydrophobic liquid containing volatile aromatic compounds extracted from plants. ... Perfume is a mixture of fragrant essential oils and aroma compounds, fixatives, and solvents used to give the human body, objects, and living spaces a pleasant smell. ... For other uses, see Cosmetic. ... 4-Aminobenzoic acid, para-aminobenzoic acid, or simply PABA, is an organic compound with molecular formula C7H7NO2. ...

Upon exposure to light, notably light containing ultraviolet radiation, discolouration of the skin (whether as inflammation, lightening or darkening) or rashes may result. In extreme cases, blistering may also occur. UV redirects here. ...

See also

• Photodermatitis
• Photosensitivity in animals
• Photoallergy