Disease patterns
Polymorphous light dermatosis and so-called “sun allergy” is the most common form of photodermatoses. Within a few hours after UV exposure, a reddened and rough skin rash with itching appears at exposed sites. The reaction is usually localized. Majorca acne is also known as “sun allergy“. As in polymorphic light dermatosis, the rash occurs mainly in spring or summer, but is not polymorphic (occurring in many shapes), but is uniform in shape with dome-shaped, coarse, 2-4 mm poplars. The rash is reminiscent of steroid acne. Numerous drugs can cause an adverse skin reaction when combined with solar radiation. Possible symptoms of photosensitivity include skin redness, pain, burning, blistering, and eczema. Underlying conditions are usually nonimmunologic phototoxicity and, less commonly, photoallergy. Rarer clinical pictures: Solar urticaria (urticaria solaris) is a rare form of urticaria (hives) in which skin redness and wheals begin within minutes of exposure to sun or artificial light. Depending on the exposure, systemic complications are possible (anaphylaxis). Hydroa vacciniforme is a very rare condition in which hemorrhagic lesions occur after sun exposure. Actinic prurigo is a rare, extreme photosensitivity with pruritic skin lesions in sun-exposed areas.
Note
Other diseases can be aggravated by sun exposure, such as lupus erythematosus. However, sun exposure is not the actual trigger. Sunburn is a normal skin reaction and therefore not included here among the photodermatoses.
