Allergies are a complex problem, and they are extremely wide- spread. The reason for allergies is that organism overreacts to certain substances, sees them as a threat. After getting into contact with a certain allergen body releases histamines and a bunch of other so called mediators – chemicals that our immune system uses to produce inflammation. Normally inflammation is our friend – it dilates blood vessels to prevent spreading of the unwanted substance. Histamine increases temperature in that local part of the body in order to kill viruses or germs that are sensitive to it (it’s a long shot but sometimes it works), increases blood vessels permeability to let antibodies and immune cells get closer to the intruder (but also gets us a runny nose). Problems occur only when the immune system starts attacking innocent things because on molecular level they are similar to some threats that our organism met before and remembered – most usually it is a protein of some kind – peanuts, pollen, parts of animal fur or insects also chemicals. You don’t want your immune system to go into crusade every time a cat walks by.
To prevent allergies there are several methods, two of them are most popular: antihistamine and steroids.
Antihistamines work against histamine – that main mediator our body uses to alert all the rest of immune system. Histamine is also responsible for most of unwanted symptoms like swelling, itching, rash, runny nose and diarrhea (yes, sometimes that is also associated with allergies).
Antihistamines can resemble histamine on a molecular level but be inactive – so they simply clog all the available receptors for histamine. In addition, some antihistamines can block histamine release from the immune cells – like Ketotifen.
There are several generations of antihistamines – they are becoming more and more selective, meaning that they have less and less of the side effects. Nowadays there are antihistamines that don’t make you sleepy some of them can even be taken with alcohol.
Antihistamines are great for prevention of allergies during the pollen season, or when you need to take away the swelling after some insect bit you. They are a good help against rush, and their side effects – sedation and sleepiness (in some of them) can be considered a useful feature when treating children or emotional patients.
Sometimes, however, they are not enough. There are situations when simply blocking histamine would not solve the problem, for histamine is very important, but not the only mediator – there are several others and then you need to calm down a much bigger part of immune system. That is when steroids are useful.
Strong swelling that can not be taken away with antihistamines, troubles breathing and life threatening conditions need immediate administration of steroids. They are also widely used to take away the skin rush in form of creams and ointments. All steroids have a more or less distinct immunosuppressive effect, so in theory most of them can be used to treat allergies. Most common are prednisone, dexamethasone and a little bit weaker but with less side effects – hydrocortisone.
They are used in scenarios when not using them can be dangerous, like when there is a chance the person might get a trouble breathing because of the swelling and constriction of bronchi. For other, non life threatening cases it is still better to use antihistamines because of significantly lesser amount of side effects. Steroids can cause increased blood pressure; suppressed immune system can lead to development of germs and fungi that would not trouble other vice. There are however, cases when steroids have to be administered on a regular basis – one of them is asthma.
Asthma is also an allergic condition only the dominant feature is the constriction of the bronchi. Regular allergies can sometimes acquire asthmatic component and if untreated become asthma.
Our immune system can learn, and if we are in contact with certain chemical or protein, that our body has allergic reaction to – the reaction can get stronger. A person that never had allergies before, when getting in contact with certain chemical every day, for example at work if working as a genitor or a hairdresser – can get allergies to certain components, and if they keep getting in contact with those allergens and getting allergic reactions that can grow into asthma. That is when steroids are prescribed on a regular basis – hydrocortisone or, more commonly, Budesonide. They are taken via inhaler, antihistamines are more commonly sold in form of pills and prednisone and dexamethasone in ampules or as a part of creams.
A tendency to allergies can be inherited, so if your parents had asthma or allergies – you should be extra careful. Nowadays there are methods to tame the immune system by injecting small doses of diluted antigen regularly, thus teaching the body to “make peace” with the intruder, but those methods are long, expensive and they don’t always work, so prevention in this case is definitely better than care.