It is a well-known fact that most autoimmune diseases which affect the skin are worsened by exposure to the sun, fluorescent lights, or even photocopiers. Lupus erythematosus is no exception to this rule.
In fact, sun sensitivity is one of the main criteria used to diagnosed lupus according to the American College of Rheumatology (1).
But how exactly does the sun affect your skin? And how can photosensitive lupus patients protect themselves from the ever-present rays of the sun? This article will look into the different mechanisms implicated in light sensitivity and also into the various strategies that can be applied to keep your lupus under control!
What exactly is lupus?
Lupus erythematosus actually refers to a group of autoimmune diseases that are characterized by the production of autoantibodies. In other words, the body’s immune system begins to malfunction and attacks many of its own organ systems, including the skin (2).
Lupus can be categorized into two main groups. Systemic lupus erythematosus is a chronic form of the illness which affects several organs including the skin, kidneys, articulations, heart, and several others (3). Cutaneous lupus is a form of the disease which chiefly affects the skin. There are different subgroups of this type of lupus, depending on the kind of skin lesion that is produced.
Acute cutaneous lupus is characterized by a butterfly-shaped rash that forms over the bridge of the nose and generally lasts only a couple of weeks. Discoid lupus produces chronic, coin-shaped, scaly rashes in areas like the head, neck, and the backs of the hands that are slightly raised and can lead to scarring (4). Subacute cutaneous lupus is a form that often starts as a widespread rash in areas regularly exposed to sunlight, has a ring-like pattern, is sometimes confused with psoriasis, and heals without scarring (5).
Causes of lupus ertyhematosus
Many factors lead to the development and progression of lupus erythematosus. Some factors are internal, like genetics, hormones, and stress levels, while others are external, such as diet quality and exposure to radiation (6).
Certain types of medication have been known to mimic the symptoms of lupus. This is known as drug-induced lupus erythematosus, and it has already been linked to over 90 drugs (7). Other medications have also been shown to increase the effects of the sun on the body through “phototoxic” reactions, such as tetracycline antibiotics (8). Both of these conditions resolve once the medication is discontinued.
Nevertheless, environmental factors are usually the main causes of frequent and uncontrollable flare-ups, and sunlight is the most important perpetrator.
Photoprotection for lupus patients
Many studies have proven the toxic effects of ultraviolet radiation on lupus patients. For example, in a recent study of 227 patients, abnormal responses to UVA/UVB irradiation were reported in up to 65% of patients with acute cutaneous lupus, producing a papular rash (9).
However, many studies have also proven the photoprotective effects on sunblock. One such study reported that broad‐spectrum sunscreen can effectively inhibit interferon, a protein responsible for many of the toxic mechanisms involved in UV-induced lupus flare-ups (10).
Another method of photoprotection is the use of topical antioxidants. Antioxidants can inhibit many proinflammatory substances which are activated through UV exposure and the resulting oxidative stress. Therefore, antioxidants can reduce or prevent the dermal inflammation that takes place in lupus.
Most types of nuts are rich sources of antioxidants called polyphenols. A study conducted in 2013 showed that the topical application of pistachio extracts to areas of skin exposed to UV radiation inhibited the production of redness and inflammation (11). Another study showed that these same protective effects were achieved by the topical application of green tea extracts, due to its polyphenolic content (12).
Yet, antioxidants that are taken orally, be it through regular diet or supplementary capsules, can also provide protection against photosensitivity.
Pomegranates, for example, have been reported to contain very high levels of antioxidants (13). Likewise, milk thistle has been proven to be a powerful antioxidant thanks to its active ingredient, silibinin (14). Carotenoids also have strong antioxidative properties and are found in many brightly colored fruits and vegetables, such as carrots, spinach, bananas, and corn (15). Thus, it would be beneficial to increase your daily intake of these foods.
Photoprotection is the key to effectively treating your lupus ertyhematosus. Basic measures to integrate into your daily routine are the use of a broad-spectrum sunscreen, sunglasses, and photoprotective clothing. Also, avoiding sun exposure during peak UV radiation hours, 11 a.m. to 4 p.m., is key.
Additionally, you need to give your immune system a little support by loading your body with antioxidants. An easy way to do this is by including fruits and vegetables into your diet that contain carotenoids, like lutein, lycopene, and beta-carotene. This includes food like tomatoes, watermelon, kale, spinach, broccoli, apricots, mangoes, and pumpkin.
Supplements rich in antioxidants can be powerful allies, as well. You should look for capsules that contain green tea extract, vitamin E, A, D, or C, selenium, and/or zinc, just to name a few.
If you follow these simple suggestions and pay close attention to your own body, you could improve your lupus symptoms faster than you ever thought possible!