HAY FEVER
SO, WHAT IS HAY FEVER ANYWAY? Hay fever, sometimes referred to as allergic rhinitis, is classically characterised by symptoms such as sneezing, runny/blocked nose, itch, and post-nasal drip, with these symptoms being brought about by the infl ammation of the mucosal tissues of the nose as a result of an allergic reaction to pollen. In addition to these symptoms, hay fever can also bring about involvement of the eyes and sinuses, leading to irritation, pain, and general discomfort for the sufferer.
From a biochemical point of view, hay fever comes about due to the sensitisation of the patient to allergens, such as tree or grass pollen. During this process, allergens are processed by antigen presenting cells (such as dendritic cells, which are present on the surface of the nasal mucosa), which then present selected peptides from the allergens on major histocompatibility complex class II molecules, with these molecules going on to bring about a chemical cascade involving a number of immune cells, such as naïve CD4+ T-cells and specifi c Th2 cells. The resultant chemicals then lead to further immune cell activity,
bringing about the production of specifi c IgE, and proliferation of cells such as eosinophils, mast cells and neutrophils3
.
Of course, some of these processes take time, with others occurring much more quickly after subsequent exposure to the trigger allergen, which is why the presence of both an “early” and “late” reaction is characteristic of hay fever in most patients. In the early stage, sneezing and rhinorrhoea can develop within 30 minutes of exposure, with the late stage taking place around 6 hours after exposure, leading to nasal blockage, which can then take time to subside. The nature of these outcomes and the time factors related to each one indicate that a range of treatments can be required for these conditions, and that it may be suitable to recommend a combination of treatments to your patients that can provide both immediate relief, as well as a long- term reduction of their hay fever symptoms.
TREATMENT STRATEGIES FOR HAY FEVER You will be aware that the range of products available for hay fever
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Moorfi elds Pharmaceuticals’ CATACROM® Sodium Cromoglicate 2% eye drops; the original single-dose preservative-free, and phosphate-free, presentation of the tried and tested ‘fi rst line’ therapy for treating and preventing allergic conjunctivitis (both seasonal and perennial) available in the UK.
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In terms of the products available, there are two main categories of molecule, namely fi rst and second-generation. First-generation antihistamines (e.g. diphenhydramine, chlorpheniramine) have been used for over half a century, and have the classical side effects of sedation, memory impairment and psychomotor dysfunction. It is also worth noting that these particular drugs can cause a number of issues if the patient has other comorbidities, so this should always be considered. The newer, second-generation molecules (incl. cetirizine, loratadine) are structured in such a way that they exhibit a signifi cantly smaller degree of
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is large and that the potential market for these products in your pharmacy is huge due to the number of sufferers and because of the duration of time that the condition can persist. However, it’s prudent to be thoughtful when recommending products to your patients – a quick web search will return many stories of disgruntled patients who have been recommended costly products which are deemed “identical” to much cheaper products which are also available over the counter, for example. As a result, it is a good idea to make sure that you reinforce the reasoning behind your recommendation of products, as this is more likely to keep your patients both happy and informed, leading to improved outcomes.
In general, hay fever should be managed using a stepwise approach, which is based on the information that you glean from your patient with regard to both the severity and duration of their symptoms. As always, appropriate questioning about these factors, in addition to the ability of the patient to comply, the safety profi le of the medication, and the cost- effectiveness of the selected product(s) are all-vital in bringing about effective condition management.
ANTIHISTAMINES As suggested by their name, antihistamines function by reducing the production of histamine, which is produced by stimulated mast cells during the early response phase of the allergic reaction. This suggests that the use of these medications is suitable for the immediate treatment of the condition, bringing about alleviation of the initial symptoms, but not having an effect on long-term infl ammation.
penetration of the blood-brain barrier, and thus, do not bring about the CNS effects of their fi rst generation cousins.
This leads on the question of when an antihistamine is the most appropriate treatment strategy. These products should be recommended fi rst-line if the patient needs an “as-required” treatment for occasional symptoms. In situations where the patient exhibits conjunctivitis as the main symptom, is aged between 2 and 5, or if the patient prefers and oral dosage form, oral products such as cetirizine or loratadine should be recommended. In all other situations where as- required treatment is the best approach, is recommended, intranasal azelastine – however, this is currently a prescription-only preparation, and thus would require the patient to be referred on in situations where its use is suitable.
There are other situations where the use of oral antihistamine is recommended as fi rst line, including for those who have a predominant symptom of sneezing or nasal discharge with associated eye involvement, prefer oral products, and require preventative treatment or control over symptoms, which are frequent or persistent. Additionally, oral antihistamines are recommended where a patient is awaiting the effect of a preventative treatment to take hold, provided that they are already using an intranasal corticosteroid.
INTRANASAL CORTICOSTEROIDS Another product type that is instrumental in the treatment of hay fever are intranasal corticosteroids. Their mechanism of action is known to be complex, but is not fully understood – there’s the potential that these drugs penetrate the nasal mucosa and act on the target immune cells in the locality of the nose, without exerting a systemic effect, which is benefi cial, and it’s also suggested that these drugs may inhibit IgE-dependent release of histamine4
.
Overall, these drugs work well to reduce the nasal effects of hay fever, and bring the patient relief.
So, when should they be recommended? These products should be given if the patient has sneezing or nasal discharge as a predominant symptom, and wants a preventative treatment for their persistent symptoms. Due to the
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