Allergy.
The meaning of the term “allergy” is altered reaction, i.e. reaction of our body to a substance in a way which is not natural or normal. Allergy is hypersensitivity disorder of our immune system. Allergic reaction occurs commonly to harmless (to majority of population) substances which are found in our natural environment in abundance, such as house dust, pollen etc. Allergen is a substance which induces allergic reaction to the individuals allergic to the allergen, but it is harmless to other individuals who are not allergic to it.
Some examples of common allergic reaction include asthma, hay fever, atopic dermatitis (commonly known as eczema), reaction to bee stings and other venomous insect stings. Many individuals are also allergic to certain types of food, known as food allergy. The most common food allergen is peanuts. Other examples of food allergens include egg, milk (cow or goat milk), prawn, shellfish, walnuts, pistachios, poppy seeds, sesame seeds etc.
What medications are available for treatment of allergy?
The groups of drugs which are used in treatment of allergy include antihistamines (examples are promethazine, pheniramine, cinnarizine, cetirizine, fexofenadine, loratadine, azalastine etc.), glucocorticoids (examples are fluticasone, budesonide, prednisolone, hydrocortisone, beclomethasone etc.), leukotriene antagonists (examples are montelukast and zafirlukast), mast cell stabilizers (cromolyn sodium, ketotifen etc.), anticholinergic drugs (examples are ipratropium bromide, tiotropium bromide etc.) etc. Any of the above groups of anti-allergy medications can be used for the treatment of allergy.
Consumption.
Most of the anti-allergy medications are taken orally, except in allergic emergencies such as anaphylaxis, when drug need to be given intravenously. Sometimes anti-allergy medications are given by nasal spray, e.g. cromolyn sodium, inhalational glucocorticoids (fluticasone, budesonide).
Antihistamines are the most commonly prescribed group of medication for treatment of allergy. The next common group is glucocorticoids. Other groups are used less frequently.
Side effects.
Side effects with antihistamines are frequent, but are mild in nature. The common side effect of antihistamines is sedation, which is less or absent in second generation antihistamines such as cetirizine, fexofenadine, loratadine etc. Less common side effects include dry mouth, blurring or vision, alteration of bowel movement, headache etc. Patients taking antihistamines should not drive motor vehicles or operate heavy machinery.
Glucocorticoids should always be used with extreme caution as they have potentially serious side effects. Side effects of glucocorticoids are retention of sodium and water, Cushing’s habitus, muscle weakness, susceptibility to infection, delayed healing, peptic ulcer, osteoporosis, cataract, glaucoma, growth retardation, fetal abnormalities, and purple stripe in skin, fragile skin etc. and many more.
Side effects of mast cell stabilizers are less frequent and include headache, nausea, weight gain, cough, throat irritation, skin rash etc.
Side effects of mast cell stabilizers are rare and include headache, rash, neuropathy etc. Anticholinergics have frequent side effects and include dryness of mouth, difficulty in swallowing and talking, flash and hot skin, blurring of vision, palpitation photophobia, hallucination etc.
