Allergy to the sun: how it manifests itself and what to do

Sun allergy is allergic photodermatosis or photoallergy. The name of the disease comes from two Greek words - phōtos, derma, that is, light, skin, and includes a fairly large group of dermatological problems caused by exposure to sunlight. Rashes and itching caused by sunlight are more correctly called not an allergy, but a false allergic reaction, since antibodies are not formed in the blood serum.

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What can trigger a sun allergy?

There are many reasons why sun allergy develops. It is believed that the provoking factors may be:

• Diseases of the liver and gallbladder.
• Gastrointestinal pathologies, enzymatic deficiency.
• Chronic kidney disease.
• Thyroid pathologies.
• Disruption of pigment (porphyrin) metabolism.
• Parasitic infection, helminthic invasion.
• Avitaminosis, especially a lack of vitamins A, PP and E.
• Uncontrolled use of medications.
• General allergic predisposition, including hereditary.

Phototoxic drugs that can cause sun allergy:

• The entire tetracycline group.
• Cytostatics.
• Corticosteroids.
• Hypoglycemic drugs.
• Sleeping pills and barbiturates.
• Oral contraceptives.
• Cardiac medications.
• Nonsteroidal anti-inflammatory drugs.
• Sulfonamides.
• Retinols.
• Salicylates.
• Neuroleptics.
• Antifungal drugs.
• Fluoroquinolones.
• Diuretics.
• Antiarrhythmic drugs.
• Vitamins B2, B6.
• Aspirin.

Plants, fruits, berries, which contain furocoumarins. Sun allergy can be provoked by such plant sensitizers:

• Quinoa.
• Buckwheat.
• Nettle.
• Buttercups.
• Fig.
• Hogweed.
• St. John's wort.
• Clover.
• Agrimony.
• Sweet clover.
• Angelica.
• Sedge.
• Rowan.
• Nuts.
• Orange.
• Lemon.
• Grapefruit.
• Caraway.
• Dill.
• Cinnamon.
• Bergamot.
• Mandarin.
• Sorrel.
• Parsley.
• Cocoa.

The mechanism of development of sun allergy

In principle, sunlight cannot be an allergen, but it can provoke several types of aggressive reactions not only of the immune system, but of the entire body:

• Phototraumatic reaction is a simple sunburn from overly “zealous” tanning.
• Phototoxic reaction is a photodermatosis caused by the interaction of ultraviolet radiation and certain types of drugs and plants.
• Photoallergy or sun allergy is photosensitivity.

All types of reactions manifest themselves in varying degrees of skin pigmentation, and in people prone to allergies, even a seemingly safe half-hour stay in the sun can cause severe allergies.

Allergy to the sun can be provoked by photosensitizers, which include many plant components, food, and medicinal substances. Photosensitizers increase the sensitivity of the skin to the effects of ultraviolet radiation, activate internal "protest" mechanisms, including an aggressive response of the immune system. Itching and rash typical for classical allergies, with false allergies are formed as a result of the formation of biologically active substances in the body - acetylcholine, histamine.

Photosensitizers, in turn, are differentiated by the speed of action – facultative and obligatory.

1. Optional substances provoke photosensitivity of the dermis very rarely, only in exceptional cases with intense exposure to sunlight and in the presence of allergic readiness. Optional substances, as a rule, provoke an allergic reaction.
2. Obligate - activate skin photosensitivity always, sometimes after almost 10-15 minutes or several hours later. Obligate sensitizers cause a phototoxic reaction.

In addition to acute symptoms such as sunburn or photodermatitis, sun allergy can cause exacerbation of eczema, herpes, acne and even psoriasis. There are photosensitizers that can accelerate the aging of the dermal coverings and contribute to the development of oncological diseases (skin cancer, melanoma).

Symptoms of sun allergy

Sun allergy most often manifests itself as photodermatoses, that is, dermal symptoms. Photodermatoses can look like the well-known sunburn, photophytodermatitis, phototoxic reaction, light eczema, pruritus, solar urticaria.

Types of photodermatoses:

• Sunburn combined with allergic reactions. This is an acute phototraumatic reaction that manifests itself as inflammation of the skin and in the last 20 years has increasingly provoked melanoma (skin cancer).
• Chronic ultraviolet radiation causes geroderma, which does not look like a classic allergy, but the processes occurring inside the body are very similar to a typical immune response to an allergen invasion. Photoaging can lead to hyperpigmentation, decreased skin turgor, increased sensitivity, and small internal rashes (hemorrhages).
• Contact with plants that are phototoxic can also provoke photodermatosis, or more precisely, "meadow" photodermatitis. Such plant sensitizers include all plants containing salicylates and coumarins.
• Solar eczema and solar pruritus are typical manifestations for which sun allergy is “famous”.
• Allergies can manifest themselves in the form of polymorphic dermatosis, that is, a light-dependent rash.

It is necessary to differentiate between photodermatitis and photodermatosis. It is quite easy, you just need to remember that the ending "it" is a fleeting, rapidly developing symptom, and the ending "oz" denotes a longer process.

Photodermatitis, which is considered toxic, is characterized by rashes on sun-exposed areas of the body: blisters appear there, which then burst, and the skin in these areas becomes pigmented.

Toxic photodermatosis is characterized by peeling and sagging skin. It becomes flabby, dry, telangiectasias appear (blood vessels burst), then hyperpigmentation develops.

Photophytodermatitis is a significant reddening of the skin, the appearance of irregular blisters, the whole body begins to itch. Hyperpigmentation is not localized, it resembles blurry patterns.

Typical photoallergic dermatitis looks like a rash, sometimes like a scattering of small blisters, the body itches, scratches. Pigmentation is extremely rare, and solar erythema is almost always present. Also, sun allergy can manifest itself as merging blisters localized on the face. Then the rash gradually spreads to the neck and down the entire body. Often, skin manifestations are accompanied by fever, headache, cheilitis (inflammation of the border of the lips), conjunctivitis.

Weeping blisters with exudate, combined with swelling of areas of the skin, indicate solar eczema.

What to do if sun allergy is severe?

The first thing you need to do is to get away from the sun's rays. Then it is advisable to immediately consult a doctor to avoid all sorts of complications. If a person is caught in a sun allergy in a place where there is no possibility of quickly getting medical help, you can take the following steps yourself:

• Wet the affected skin as much as possible with cucumber or watermelon juice.
• Apply cabbage juice mixed with beaten egg white to the skin.
• Lubricate the blisters with a mixture of honey and water.
• Dilute apple cider vinegar with water in a 1/1 ratio and apply the solution to the damaged skin.
• Make compresses from strong black tea (cooled).
• Lubricate the affected areas of the skin with a decoction of calendula or succession.
• Apply methyluracil ointment to the inflamed areas of the skin or lubricate them with a furacilin solution.
• Take a niacin (nicotinic acid) tablet orally, preferably after meals.

Of course, the best way to treat sun allergy is to have a reasonable attitude towards ultraviolet radiation. Even if you have not had any allergic symptoms to sun rays, it is better not to provoke your body, because it is common knowledge that solar activity increases every year.