Photodermatitis, sometimes referred to as sun poisoning or photoallergy, is a form of allergic contact dermatitis in which the

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms ...

must be activated by light to sensitize the allergic response, and to cause a

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cr ...

or other systemic effects on subsequent exposure. The second and subsequent exposures produce photoallergic skin conditions which are often

eczema Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...

tous. It is distinct from sunburn.

Signs and symptoms

Photodermatitis may result in swelling, difficulty breathing, a burning sensation, a red itchy

sometimes resembling small

blisters A blister is a small pocket of body fluid (lymph Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the ...

, and peeling of the skin.

Nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

may also occur. There may also be blotches where the itching may persist for long periods of time. In these areas an unsightly orange to brown tint may form, usually near or on the face.

Causes

Many medications and conditions can cause sun sensitivity, including: *

Sulfa Sulfonamide is a functional group (a part of a molecule) that is the basis of several groups of drugs, which are called sulphonamides, sulfa drugs or sulpha drugs. The original antibacterial sulfonamides are synthetic (nonantibiotic) antimi ...

used in some drugs, among them some antibiotics, diuretics, COX-2 inhibitors, and diabetes drugs. * Psoralens,

coal tar Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasi ...

s, photo-active dyes ( eosin, acridine orange) * Musk ambrette,

methylcoumarin Methylcoumarin is one of a series of isomers in which a methyl group substitutes for a hydrogen atom in coumarin Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a ben ...

, lemon oil (may be present in fragrances) * PABA (found in sunscreens) *

Oxybenzone Oxybenzone or benzophenone-3 or BP-3 (trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3) is an organic compound. It is a pale-yellow solid that is readily soluble in most organic solvents. Oxybenzone belongs to the class of aroma ...

(UVA and UVB chemical blocker also in sunscreens) * Salicylanilide (found in industrial cleaners) *

St John's Wort ''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus ''Hypericum''. Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found a ...

* Hexachlorophene (found in some prescription antibacterial soaps) *

Tetracycline antibiotics Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of ''Streptomyces'' bacteria or produced semi-synthetically from those isolated compounds. T ...

(e.g.,

tetracycline Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including Acne vulgaris, acne, cholera, brucellosis, plague (disease), plague, malaria, and sy ...

doxycycline Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, an ...

minocycline Minocycline, sold under the brand name Minocin among others, is a tetracycline antibiotic medication used to treat a number of bacterial infections such as pneumonia. It is generally less preferred than the tetracycline doxycycline. It is also ...

) *

Benzoyl peroxide Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula , often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (, Bz) groups connected by a peroxide () ...

Retinoid The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth. Retinoids have many important functions throughout t ...

s (e.g.,

isotretinoin Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers (squamous-cell carcinoma), and in th ...

) * Some NSAIDs (e.g.,

ibuprofen Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arte ...

naproxen sodium Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulati ...

) *

Fluoroquinolone antibiotic A quinolone antibiotic is a member of a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well ...

Sparfloxacin Sparfloxacin is a fluoroquinolone antibiotic used in the treatment of bacterial infections. It has a controversial safety profile. It was patented in 1985 and approved for medical use in 1993. Zagam is no longer available in the United States. ...

in 2% of cases * Amiodarone, used to treat atrial fibrillation * Pellagra (

Vitamin B3 Vitamin B3, colloquially referred to as niacin, is a vitamin family that includes three forms or vitamers: niacin (nicotinic acid), nicotinamide (niacinamide), and nicotinamide riboside. All three forms of vitamin B3 are converted within the bo ...

deficiency) Photodermatitis can also be caused by plants such as ''

Ammi majus ''Ammi majus'', commonly called bishop's flower, false bishop's weed, laceflower, bullwort, etc., is a member of the carrot family Apiaceae. The plant, which has white lace-like flower clusters, has a large distribution through Southern Europe, ...

'', parsnip, giant hogweed (''

Heracleum mantegazzianum ''Heracleum mantegazzianum'', commonly known as giant hogweed, is a monocarpic perennial herbaceous plant in the carrot family Apiaceae. ''H. mantegazzianum'' is also known as cartwheel-flower, giant cow parsley, giant cow parsnip, or hogs ...

''), common rue (''

Ruta graveolens ''Ruta graveolens'', commonly known as rue, common rue or herb-of-grace, is a species of '' Ruta'' grown as an ornamental plant and herb. It is native to the Balkan Peninsula. It is grown throughout the world in gardens, especially for its blui ...

''), and ''

Dictamnus ''Dictamnus'' is a genus of flowering plant in the family Rutaceae, native to temperate Eurasia from Spain to China. The genus was first described by Carl Linnaeus in 1753. Species , Plants of the World Online accepted two species: *''Dictamnus ...

'', a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

flowering plants Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the family Rutaceae with a single species ''Dictamnus albus'', commonly called the burning bush. Photodermatitis caused by plants is called phytophotodermatitis.

Prevention

Prevention includes avoiding exposure to chemicals that can trigger the reaction, such as by wearing gloves, or avoiding sunlight or wearing

sunscreen Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn and ...

preferably with at least factor 30 and with a high UVA protection level on the affected area. And by addressing any risk factors, such as those listed above.

References

External links

{{Authority control Skin conditions resulting from physical factors

Signs and symptoms

Causes

Prevention

See also

References

External links