pinpoint red dots on skin after being in sun

Sometimes they spare areas that are habitually exposed to the light, eg the face in polymorphic light eruption.

Photodermatoses affect areas exposed to sunlight (face, neck, hands) and do not affect areas not exposed to the light (covered at least by underwear), or are less severe in covered areas.The clinical features depend on the specific photodermatosis. What are the clinical features of photosensitivity? Porphyria is mainly triggered by exposure to visible light. UVA is blocked by polycarbonate and densely woven fabric.UVA can penetrate untreated and untinted glass, which blocks UVB.UVA can penetrate through the epidermis into the dermis thus UVA damages more deeply than UVB.UVA is however 100 times more prevalent at the earth’s surface than UVB.UVA is of lower energy than UVB, thus photon for photon, UVA is less damaging than UVB to DNA in skin cells.Present throughout the day, but there is more UVA around the solar noon that earlier or later.Present throughout the year, but there is more UVA during summer.The most common photosensitivity is to UVA. only to UVB, UVA or visible light) or to a wider range of radiation. Patients can be sensitive to one kind of sunlight (i.e. UVA: longer wavelength rays 320–400 nm that cause tanning and also suppress immune reactions in the skin.UVB: short-wavelength rays 290–320 nm that cause sunburn and tan.UVC: ultrashort wavelength rays 200–290 nm that do not reach the earth’s surface.The electromagnetic spectrum ranges from cosmic rays, invisible rays called ultraviolet radiation ( UVR), through visible light, to infrared, microwaves and radio waves. Photosensitivity is caused by an abnormal reaction to some component of the electromagnetic spectrum of sunlight and a chromophore (reactive compound) within the skin. Photosensitivity can be associated with a pre-existing genetic disorder. It may be primary due to inadequate dietary intake, genetic (Hartnup disease), or secondary such as drug-induced or malabsorption. Pellagra, due to vitamin B3 (niacin) deficiency usually presents initially with photosensitivity. Erythropoeitic porphyria (Gunther disease).Clinical presentation depends on which enzyme is defective. There are genetic defects in various enzymes, and the diseases may be activated by exposure to certain medications or toxins. The most common disorders of this type are porphyrias, in which phototoxic porphyrins accumulate in the skin. Photosensitivity can be caused by a metabolic defect. Pseudoporphyria: induced by drugs and/or renal insufficiency.Photocontact dermatitis: due to phototoxic chemicals such as psoralens in plants, vegetables, fruit, fragrances in cosmetics, sunscreen chemicals, dyes, and disinfectants.Drug-induced photosensitivity: common photosensitising drugs are thiazides, tetracyclines, non-steroidal anti- inflammatory drugs ( NSAIDs), phenothiazines, voriconazole, quinine, vemurafenib.Exogenous photodermatosesĮxogenous photodermatoses are those in which phototoxic or photoallergic reaction is caused by an external photosensitiser. With the exception of polymorphic light eruption and juvenile spring eruption, these disorders are rare. Hydroa vacciniforme (associated with Epstein-Barr virus).Chronic actinic/photosensitivity dermatitis.Exposure to the sun produces a clearly defined disease entity. The causes of primary or idiopathic photodermatoses have not yet been discovered. Photosensitivity is classified into the following groups: Primary photodermatoses These fair skinned individuals do not have a photodermatosis. People with very white skin who don’t tan on exposure to the sun ( Fitzpatrick skin type 1), especially if they also have red hair and blue eyes, are often considered photosensitive, relative to people with darker skin phototypes who tan more easily. Genetic and environmental factors are involved. Different types of photosensitivity may be prevalent at different times of life. Photosensitivity occurs in males and females of all races and at all ages.

Pinpoint red dots on skin after being in sun