| Photodermatosis | |
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| Specialty | Dermatology  |
Photodermatoses is a skin condition resulting in abnormal skin reactions to ultraviolet (UV) radiation. [1] These abnormal skin reactions may develop into rashes. While reactions to UV radiation is common, true photodermatoses is considered when an abnormal reaction is caused by UV-A rays or radiation between 320 and 400 nm. [2]
Photodermatoses can be categorized into primary or secondary photodermatoses based on the cause of the reaction. Primary photodermatoses are immunology mediated or caused by chemical/drug exposure. An example of primary photodermatoses is Polymorphous light eruption. Polymorphous light eruption is the most common type of photodermatoses. It is most likely due to an abnormal immune system reaction to the sun. Polymorphous light eruption occurs in approximately 10 to 20 percent [3] of otherwise healthy individuals, so it is a relatively common condition. A more rare photodermatoses is hydroa vacciniforme with a prevalence of 0.34 per 100 000. [2]
Secondary photodermatoses stems from underlying disorders including genetic diseases and photoaggravated dermatoses. [4]
There are several ways in which medical professional can diagnose photodermatoses. Usually a detailed history of the patient's experience and medical history along with physical examination is sufficient for diagnosis. The medical professional takes into consideration the time since sun exposure; use of creams/makeup, medications, and contact with plants; frequency of pruritis; improvements with less exposure to sun such as during winter months; and family history of photodermatoses. Physical examinations look for signs of erythematous rashes and swelling of areas exposed to sun, including face, upper neck or back, and primary skin lesions which includes vesicle and blisters. [2] [4]
For diagnostic uncertainty of photodermatoses, a medical professional may use other means to diagnose. Lab studies, skin biopsy, challenge-rechallenge testing, and phototesting are some options. Challenge-rechallenge testing is done by withdrawing and reintroducing the suspected cause and checking for reaction. [4] [5] Phototesting is typically done by a specialist and evaluates for primary photodermatoses. It is also the method used to identify drug related photo-toxicity. [5] There are three main methods of phototesting: Minimal erythema dose (MED) testing, Photoprovocation test, and Photopatch testing.
Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are not contagious or life-threatening, but can be very uncomfortable.
Light therapy, also called phototherapy or bright light therapy is the exposure to direct sunlight or artificial light at controlled wavelengths in order to treat a variety of medical disorders, including seasonal affective disorder (SAD), circadian rhythm sleep-wake disorders, cancers, and skin wound infections. Treating skin conditions such as neurodermatitis, psoriasis, acne vulgaris, and eczema with ultraviolet light is called ultraviolet light therapy.
Actinism is the property of solar radiation that leads to the production of photochemical and photobiological effects. Actinism is derived from the Ancient Greek ἀκτίς, ἀκτῖνος. The word actinism is found, for example, in the terminology of imaging technology, medicine, and chemistry, and the concept of actinism is applied, for example, in chemical photography and X-ray imaging.
Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis, is a pre-cancerous area of thick, scaly, or crusty skin. Actinic keratosis is a disorder of epidermal keratinocytes that is induced by ultraviolet (UV) light exposure. These growths are more common in fair-skinned people and those who are frequently in the sun. They are believed to form when skin gets damaged by UV radiation from the sun or indoor tanning beds, usually over the course of decades. Given their pre-cancerous nature, if left untreated, they may turn into a type of skin cancer called squamous cell carcinoma. Untreated lesions have up to a 20% risk of progression to squamous cell carcinoma, so treatment by a dermatologist is recommended.
Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. The photosensitive ganglion cells in the mammalian eye are a separate class of light-detecting cells from the photoreceptor cells that function in vision.
PUVA is an ultraviolet light therapy treatment for skin diseases: vitiligo, eczema, psoriasis, graft-versus-host disease, mycosis fungoides, large plaque parapsoriasis, and cutaneous T-cell lymphoma, using the sensitizing effects of the drug psoralen. The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA.
Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision, human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury. Some drugs have a photosensitizing effect. Properties of natural or artificial light that may abnormally affect people include:
Phototoxicity, also called photoirritation, is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity.
A radiation burn is a damage to the skin or other biological tissue and organs as an effect of radiation. The radiation types of greatest concern are thermal radiation, radio frequency energy, ultraviolet light and ionizing radiation.
Polymorphous light eruption (PLE) presents with itchy red small bumps on sun-exposed skin, particularly face, neck, forearms and legs. It generally appears 30 minutes to a few hours after sun exposure and may last between one and 14 days. The bumps may become small blisters or plaques and may appear bloody,often healing with minimal scarring.
Skin care or skincare is a range of practices that support skin integrity, enhance its appearance, and relieve skin conditions. They can include nutrition, avoidance of excessive sun exposure, and appropriate use of emollients. Practices that enhance appearance include the use of cosmetics, botulinum, exfoliation, fillers, laser resurfacing, microdermabrasion, peels, retinol therapy, and ultrasonic skin treatment. Skin care is a routine daily procedure in many settings, such as skin that is either too dry or too moist, and prevention of dermatitis and prevention of skin injuries.
Solar urticaria (SU) is a rare condition in which exposure to ultraviolet or UV radiation, or sometimes even visible light, induces a case of urticaria or hives that can appear in both covered and uncovered areas of the skin. It is classified as a type of physical urticaria. The classification of disease types is somewhat controversial. One classification system distinguished various types of SU based on the wavelength of the radiation that causes the breakout; another classification system is based on the type of allergen that initiates a breakout.
Discoid lupus erythematosus is the most common type of chronic cutaneous lupus (CCLE), an autoimmune skin condition on the lupus erythematosus spectrum of illnesses. It presents with red, painful, inflamed and coin-shaped patches of skin with a scaly and crusty appearance, most often on the scalp, cheeks, and ears. Hair loss may occur if the lesions are on the scalp. The lesions can then develop severe scarring, and the centre areas may appear lighter in color with a rim darker than the normal skin. These lesions can last for years without treatment.
Phytophotodermatitis, also known as berloque dermatitis or margarita photodermatitis, is a cutaneous phototoxic inflammatory reaction resulting from contact with a light-sensitizing botanical agent followed by exposure to ultraviolet light. Symptoms include erythema, edema, blisters, and delayed hyperpigmentation. Heat and moisture tend to exacerbate the reaction.
Afamelanotide, sold under the brand name Scenesse, is a medication used to prevent phototoxicity and to reduce pain from light exposure for people with erythropoietic protoporphyria. It is a melanocortin 1 receptor (MC1-R) agonist and a synthetic peptide and analogue of α-melanocyte stimulating hormone. It is administered as subcutaneous implant.
Chronic actinic dermatitis is a condition where a subject's skin becomes inflamed due to a reaction to sunlight or artificial light; similar to solar urticaria or cholinergic urticaria. Patients often have other related conditions of the skin that cause dermatitis in response to a variety of stimuli.
In medicine, a drug eruption is an adverse drug reaction of the skin. Most drug-induced cutaneous reactions are mild and disappear when the offending drug is withdrawn. These are called "simple" drug eruptions. However, more serious drug eruptions may be associated with organ injury such as liver or kidney damage and are categorized as "complex". Drugs can also cause hair and nail changes, affect the mucous membranes, or cause itching without outward skin changes.
Actinic prurigo is a rare sunlight-induced, pruritic, papular, or nodular skin eruption. Some medical experts use the term actinic prurigo to denote a rare photodermatosis that develops in childhood and is chronic and persistent; this rare photodermatosis, associated with the human leukocyte antigen HLA-DR4, is often called "Familial polymorphous light eruption of American Indians" or "Hereditary polymorphous light eruption of American Indians" but some experts consider it to be a variant of the syndrome known as polymorphous light eruption (PMLE). Some experts use the term actinic prurigo for Hutchinson's summer prurigo and several other photodermatoses that might, or might not, be distinct clinical entities.
Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness. Other symptoms include blistering, peeling skin, swelling, itching, and nausea. Excessive UV radiation is the leading cause of (primarily) non-malignant skin tumors, which in extreme cases can be life-threatening. Sunburn is an inflammatory response in the tissue triggered by direct DNA damage by UV radiation. When the cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the tissue is replaced.
Acne aestivalis also called as acne mallorca, is a special kind of polymorphous light eruption induced by ultra violet A radiation. This condition is said to be seasonal, usually affecting people in springtime and goes away in autumn when there is less sun light. This photo induced skin reaction leads to a mono-morphous eruption that consists of multiple, uniform, red, papular lesions. This skin reaction is classified as a delayed-type hypersensitivity because the onset is 24–72 hours after sun exposure. The condition equally affects men and women between the ages of 20–40 years old with no prior history of acne vulgaris. The eruption is unusual because it spares the face but it affects the lateral aspects of the upper arms, shoulder girdle, back, and chest. This condition's pathogenesis is not very well understood but scientists believe it an unfortunate side effect that results from a strong immune response to potentially cancer-causing cell damage.
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