Photosensitivity refers to various symptoms, diseases, and conditions (photodermatoses) caused or exacerbated by exposure to sunlight. It is classified into five categories: primary photodermatosis, exogenous photodermatosis, photo-exacerbated dermatoses, metabolic photodermatosis, and genetic photodermatosis.
Primary or autoimmune photodermatoses
Photo-exacerbated or photo-aggravated dermatoses
Metabolic photodermatoses (rare)
Genetic photodermatoses (very rare disorders due to genomic instability)
The etiology of a photodermatosis depends on its classification (see individual topic articles). Some are due to autoimmune reactions, drugs, connective tissue disease, and abnormal inherited biochemical pathways.
Photosensitivity may be observed in both males and females at all ages and in all ethnic groups. Different types of photosensitivity may be prevalent at different times of life. Genetic and environmental factors intervene in the occurrence of photosensitivity.
Photosensitivity is caused by an abnormal reaction to a component of the electromagnetic spectrum of sunlight and a chromophore (reactive compound) within the skin. Patients can be sensitive to one kind of sunlight, for example only to ultraviolet radiation, ultraviolet A or B (UVA, UVB), or visible light, or to a wider range of radiation. The most common photosensitivity is to UVA. Mainly, exposure to visible light triggers porphyria.
The clinical features depend on the specific photodermatosis.
Clues to photosensitivity include:
Medical practitioners diagnose photosensitivity by a history of a skin problem arising from exposure to sunlight. They determine the specific type by taking a careful history, examining the skin and performing specific tests. Photosensitivity is sometimes confirmed by photosets, which only is available in specialized centers.
Investigations may include:
Management of photosensitivity involves sun protection and treatment of the underlying disorder. Mainly, photosensitivity reactions are prevented by careful protection from sun exposure and avoidance of exposure to artificial sources of UVR. Use of websites and smartphone apps that indicate local ultraviolet levels are helpful to understand when protection is most essential. There is more ultraviolet radiation in the tropics compared to temperate areas, in the Southern hemisphere compared to the Northern, during summer compared to winter, at high altitude compared to sea level, and in the middle of the day compared to the extremes of the day.
SPF is sun protection factor, defined as the dose of solar radiation needed to induce just perceptible erythema (minimal erythema dose, MED) on skin treated with 2 mg/cm sunscreen divided by the MED on untreated skin. SPF primarily describes protection from UVB, as it reflects protection from the erythema action spectrum.
The primary photodermatosis polymorphic light eruption may be paradoxically effectively treated by graduated, and cautious, exposure to ultraviolet radiation.
Patients with photodermatoses also may need to:
The healthcare team, including nurses, pharmacists, and clinicians must work together to educate patients with photodermatoses as they need to be reminded to take vitamin D supplements and oral antioxidants, wear a clear plastic mask to protect the face, choose gray-tinted laminated glass for their automobile, and apply photoprotective UV films to windows at home, school work, and vehicles. The team should remind patients they need to have regular skin checks to locate and treat skin cancers early. [Level V]
|||Lehmann P,Schwarz T, Photodermatoses: diagnosis and treatment. Deutsches Arzteblatt international. 2011 Mar; [PubMed PMID: 21442060]|
|||Lembo S,Raimondo A, Polymorphic Light Eruption: What's New in Pathogenesis and Management. Frontiers in medicine. 2018; [PubMed PMID: 30250845]|
|||Pile HD,Crane JS, Actinic Prurigo 2019 Jan; [PubMed PMID: 29763132]|
|||Photiou L,Foley P,Ross G, Solar urticaria - An Australian case series of 83 patients. The Australasian journal of dermatology. 2018 Dec 25; [PubMed PMID: 30585308]|
|||Paek SY,Lim HW, Chronic actinic dermatitis. Dermatologic clinics. 2014 Jul; [PubMed PMID: 24891057]|
|||Ahad T,Rhodes LE, Haemorrhagic vesicles and varioliform scarring: consider photosensitivity. Archives of disease in childhood. 2018 Nov 13; [PubMed PMID: 30425076]|
|||Blakely KM,Drucker AM,Rosen CF, Drug-Induced Photosensitivity-An Update: Culprit Drugs, Prevention and Management. Drug safety. 2019 Mar 19; [PubMed PMID: 30888626]|
|||Ibbotson S, Drug and chemical induced photosensitivity from a clinical perspective. Photochemical [PubMed PMID: 30283959]|
|||Snyder M,Turrentine JE,Cruz PD Jr, Photocontact Dermatitis and Its Clinical Mimics: an Overview for the Allergist. Clinical reviews in allergy [PubMed PMID: 29951786]|
|||Velander MJ,Þorsteinsdóttir S,Bygum A, [Clinical review of pseudoporphyria]. Ugeskrift for laeger. 2015 Feb 2; [PubMed PMID: 25650579]|
|||Foering K,Chang AY,Piette EW,Cucchiara A,Okawa J,Werth VP, Characterization of clinical photosensitivity in cutaneous lupus erythematosus. Journal of the American Academy of Dermatology. 2013 Aug; [PubMed PMID: 23648190]|
|||Auriemma M,Capo A,Meogrossi G,Amerio P, Cutaneous signs of classical dermatomyositis. Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia. 2014 Oct; [PubMed PMID: 25014587]|
|||Baba T,Yaoita H, UV radiation and keratosis follicularis. Archives of dermatology. 1984 Nov; [PubMed PMID: 6497416]|
|||Murphy G, Ultraviolet light and rosacea. Cutis. 2004 Sep; [PubMed PMID: 15499753]|
|||Suggs AK,Hamill SS,Friedman PM, Melasma: update on management. Seminars in cutaneous medicine and surgery. 2018 Dec; [PubMed PMID: 30475935]|
|||Igawa K,Matsunaga T,Nishioka K, Involvement of UV-irradiation in pemphigus foliaceus. Journal of the European Academy of Dermatology and Venereology : JEADV. 2004 Mar; [PubMed PMID: 15009310]|
|||Ellenbogen E,Wesselmann U,Hofmann SC,Lehmann P, Photosensitive atopic dermatitis--a neglected subset: Clinical, laboratory, histological and photobiological workup. Journal of the European Academy of Dermatology and Venereology : JEADV. 2016 Feb; [PubMed PMID: 26523351]|
|||Palmer RA,Hawk JL, Light-induced seborrhoeic eczema: severe photoprovocation from subclinical disease. Photodermatology, photoimmunology [PubMed PMID: 14738536]|
|||Wolf P,Weger W,Patra V,Gruber-Wackernagel A,Byrne SN, Desired response to phototherapy vs photoaggravation in psoriasis: what makes the difference? Experimental dermatology. 2016 Dec; [PubMed PMID: 27376966]|
|||Tiwary AK, Actinic Lichen Planus. Indian pediatrics. 2018 Aug 15; [PubMed PMID: 30218531]|
|||Rodríguez-Pazos L,Gómez-Bernal S,Rodríguez-Granados MT,Toribio J, Photodistributed erythema multiforme. Actas dermo-sifiliograficas. 2013 Oct; [PubMed PMID: 23962583]|
|||Haber R,Ram-Wolff C,Laly P,Bouaziz JD,Jachiet M,Rivet J,Bagot M, Photo-sensitive mycosis fungoides: a new variant? European journal of dermatology : EJD. 2017 Apr 1; [PubMed PMID: 27869099]|
|||Singal AK, Porphyria cutanea tarda: Recent update. Molecular genetics and metabolism. 2019 Jan 18; [PubMed PMID: 30683557]|
|||Wang B,Rudnick S,Cengia B,Bonkovsky HL, Acute Hepatic Porphyrias: Review and Recent Progress. Hepatology communications. 2019 Feb; [PubMed PMID: 30766957]|
|||Erwin AL,Desnick RJ, Congenital erythropoietic porphyria: Recent advances. Molecular genetics and metabolism. 2018 Dec 27; [PubMed PMID: 30685241]|
|||Lehmann J,Seebode C,Martens MC,Emmert S, Xeroderma Pigmentosum - Facts and Perspectives. Anticancer research. 2018 Feb; [PubMed PMID: 29374753]|
|||Hafsi W,Badri T, Cockayne Syndrome 2019 Jan; [PubMed PMID: 30252254]|
|||Yew YW,Giordano CN,Spivak G,Lim HW, Understanding photodermatoses associated with defective DNA repair: Photosensitive syndromes without associated cancer predisposition. Journal of the American Academy of Dermatology. 2016 Nov; [PubMed PMID: 27745642]|
|||Hafsi W,Badri T, Bloom Syndrome (Congenital Telangiectatic Erythema) 2019 Jan; [PubMed PMID: 28846287]|
|||Giordano CN,Yew YW,Spivak G,Lim HW, Understanding photodermatoses associated with defective DNA repair: Syndromes with cancer predisposition. Journal of the American Academy of Dermatology. 2016 Nov; [PubMed PMID: 27745641]|
|||Gozali MV,Zhou BR,Luo D, Update on treatment of photodermatosis. Dermatology online journal. 2016 Feb 17; [PubMed PMID: 27267185]|
|||Guarrera M, Polymorphous Light Eruption. Advances in experimental medicine and biology. 2017; [PubMed PMID: 29124691]|