What is Photocontact Dermatitis?
Photocontact dermatitis is a manifestation of contact dermatitis. It is sometimes called ‘photoaggravated dermatitis’ as a more accurate, clear definition of its actual nature. It may ultimately manifest as a form of irritant contact dermatitis or allergic contact dermatitis, depending.
The rudimentary principle of photocontact dermatitis is this: some substances are not harmful until ultraviolet radiation, such as that which is emitted by the sun, contact them and activate them. Usually, this activation results in the production of a secondary substance that is harmful, although it may also result in the substance itself becoming a toxin. This varies from substance to substance. In any case, it results in a rash, in the same manner as other forms of contact dermatitis. The product may be an allergen, provoking allergic contact dermatitis in some individuals, or it may be an irritant, provoking irritant contact dermatitis.
Who gets Photocontact Dermatitis?
Photocontact dermatitis may affect anyone. It serves as an awkward sub-category to contact dermatitis in that it partially subsumes both irritant contact dermatitis and allergic contact dermatitis. Thus, most individuals are subject to photocontact dermatitis such as it may result in exposure to irritating substances, and some other individuals are vulnerable to it in that it may result in exposure to substances they are allergic to.
The very young and very old have a tendency to be more vulnerable to photocontact dermatitis. They have a tendency to be more vulnerable to ultraviolet radiation in general, however, frequently prompting they or their guardians to protect them from sunlight.
Those most vulnerable are those that are frequently exposed to sunlight. The more skin is in contact with sunlight, the greater the risk. Because ultraviolet radiation is the trigger, direct sunlight is not necessarily required. An individual sitting in an office with a window is at risk just as a lifeguard on a beach is at risk. However, the individual in the office may find that they are only vulnerable on one side, and even further find that only their hand is affected, as this is the only part of their body truly exposed to the sun regularly. The lifeguard, however, might find that their entire body is subject to photocontact dermatitis.
What causes Photocontact Dermatitis?
Photocontact dermatitis is caused by two things: a photosensitive substance and the catalyst of ultraviolet radiation. Ordinarily, this photosensitive substance will be harmless to the afflicted individual, but if the substance should be exposed to sunlight as a catalyzing element, the substance will react or otherwise be activated, causing it to change its chemical structure or begin to produce a different substance entirely. In any case, the exposure to sunlight (specifically the ultraviolet radiation) causes it to become dangerous to skin health, resulting in an outbreak of a rash. This is photocontact dermatitis.
Photocontact dermatitis should not be confused with sunburn. While the sun’s rays can be quite harmful to skin, especially among those that aren’t careful, photocontact dermatitis has nothing to do with the damage caused by ultraviolet radiation. It refers only to cases of dermatitis made to occur because of photosensitive substances being catalyzed into irritants or allergens following exposure to the sun.
Once this catalyzation has occurred, the body undergoes an immune response. This may be the same response it would undergo in response to an irritant or the same response it would undergo in response to an allergen. This depends upon what changes the substance undergoes or what it begins to produce after it has been catalyzed by the sun’s rays. In any case, the body’s immune system responds, and this is what causes the resulting rash.
What does Photocontact Dermatitis cause?
Photocontact dermatitis causes a rash. This rash is very similar to the rash that can be produced by allergic contact dermatitis and irritant contact dermatitis, with the same potential variations cropping up in response to the variations in the body’s reaction. The rash presents with erythmia (redness) primarily, along with pain, inflammation, pruritis, and in some circumstances pustules and hives (such as when the substance catalyzed by the sunlight is an allergen).
Photocontact dermatitis may or may not provoke an immune response against the body’s own cells in the same way that allergic contact dermatitis does. If this should occur, every subsequent case of photocontact dermatitis may be more severe as a result of the body’s heightened response to the catalyzed allergen.
How serious is Photocontact Dermatitis?
Photocontact dermatitis is a reasonably serious condition. Much like allergic contact dermatitis and irritant contact dermatitis, however, how serious the condition is varies widely in response to how severe the actual symptoms at hand are. Photocontact dermatitis, while reasonably serious as a rule, can also be very severe or merely a nuisance, depending upon circumstances.
If photocontact dermatitis is occurring because one is using a new skin treatment for the first time and was exposed to the sun following it, causing the treatment to catalyze into or react to produce an irritant, photocontact dermatitis is no more serious than the rash it causes. In this circumstance, it is simply a matter of avoiding that scenario again: if the treatment is medically necessary, or simply desirable, then it is now known that any sun contact should be avoided following application of the treatment. This may already be contraindicated by the directions enclosed with the treatment, if this is a common issue. In this circumstance it is simply a matter of getting rid of the rash and not repeating the action that caused the rash.
If photocontact dermatitis is occurring because something applied to the skin has catalyzed into an allergen, it is considerably more serious. Allergic reactions bring the immune system to bear, and cause the formation of t-cells. T-cells tell the body’s immune system what to attack. In an allergic reaction, allergens bind with the skin cells, making them look like threats to the immune system, which will then assault the actually-healthy skin cells. This is a far more serious condition because it is cumulative; every subsequent case produces more t-cells and makes the body’s immune response faster and more severe. This is excellent when dealing with the pathogens for other ailments, as it means that the body will shake them off more quickly with each passing case. However, when the immune system is triggered erroneously, it just means a more severe rash to deal with.
Photocontact dermatitis is also serious in that it is a harbinger for skin irritants and allergies alike. If an outbreak of photocontact dermatitis occurs, it means that something is wrong and needs to be dealt with; even a minor case of photocontact dermatitis is serious for what it indicates. However, it is not always clear that photocontact dermatitis is the cause of the rash, making this somewhat more complex.
What does Photocontact Dermatitis treatment look like?
Treatment for photocontact dermatitis varies more than treatment for irritant contact dermatitis or allergen contact dermatitis. With allergen contact dermatitis and irritant contact dermatitis, the initial response is always to strip away the irritant or the allergen as best as possible. This is usually accomplished with a light wash using water and soap, with very, very light and gentle scrubbing. This remains the first step with photocontact dermatitis.
However, with both irritant contact dermatitis and allergen contact dermatitis, the follow-up is to avoid the irritant or allergen as best as possible. This usually involves changing one’s habits to avoid it entirely, especially for allergens. But with photocontact dermatitis, there is a third path: avoid the sunlight.
Because photocontact dermatitis revolves around activation by sunlight, this third option is available. If the possible irritant or allergen is not let to expose itself to the skin by being catalyzed by ultraviolet radiation, there will be no case of dermatitis to deal with. Skin treatments that can potentially be catalyzed into something harmful in this fashion will generally have this indicated as a direction already and inform users to avoid the sun. However, it may be independently adopted by anyone savvy enough to do so: it isn’t necessary to avoid the substance if it’s possible to avoid what causes the substance to catalyze into something harmful. This avoidance may be accomplished by way of gloves, long sleeves or long pants, a wide-brimmed hat, an umbrella or any other physical means by which to block ultraviolet rays (sunblock would not be reliable for this purpose). What method is most effective depends entirely upon where the photoreactive substance is applied or where the exposure occurred, however.
How do I know if I have Photocontact Dermatitis?
Photocontact dermatitis can be somewhat more difficult to identify than either allergic contact dermatitis or irritant contact dermatitis. There are several reasons for this. The first is that the rash is likely to be very similar to that resulting from irritant contact dermatitis and allergic contact dermatitis. The two are difficult enough to distinguish as it is, and photocontact dermatitis is nothing more than an additional vector to either of them. The second reason is that there is more than one factor at work causing a dermatitis outbreak. With irritant contact dermatitis, there is exposure to an irritating chemical followed by a dermatitis outbreak. This is cut-and-dried and very simple. With allergic contact dermatitis, it becomes somewhat more difficult in that there is usually a delay between the exposure and the rash, but there is still a direct cause and effect. With photocontact dermatitis, however, there is the initial exposure to the photoreactive substance followed then by its reaction to sunlight followed finally by the rash, or, there is the initial exposure to the photoreactive substance followed then by its reaction to sunlight followed then by a waiting period followed then by the immune response and rash.
Luckily, once photocontact dermatitis has been identified, determining what is actually causing it is much easier. There are fewer substances that can bring about photocontact dermatitis than there are that can bring about irritant contact dermatitis or allergic contact dermatitis. Patch-testing may be called for to identify allergens if the reaction is indeed an allergic one.