Hay fever (allergic rhinitis)

Treatment options and how they work?

-Intranasal corticosteroids: similar effect to antihistamine -Decongestants: reduce the swelling in the blood vessels in your nose so it helps open airways by stimulating the alpha-adrenergic receptor -Mast cell stabilisers: stop histamine being released -antihistamines: Histamine is a basic amine that acts as an AGONIST at a family of G-protein-coupled reactions (GPCR). The H1 receptor is the subtype primarily involved in allergic reactions. Antihistamines act as inverse agonists, by stabilising the receptor in its inactive state, thereby preventing its activation by histamine.

Treatment - Sodium Cromoglycate (eye drops)

-Prevents mast cell degranulation and thus histamine release - 1-2 drops to be used in each eye 4 times a day -Provides relief from itchy eyes of allergic conjunctivitis -Recommended for prophylactic use

Treatment - Oral decongestants

-Pseudoephedrine -Effective treatment for nasal congestion in hay fever Common side effects: he ache, insomnia only one pack per customer (12x60mg);subject to misuse

Treatment - Nasal Decongestants

-Used to relive symptoms of rhinorrhoea and nasal congestion -May be administered orally or topically. Rapid vaso-constrcting effect Side effect: Rebound congestion when used topically for a prolonged period of time Patient counselling: Do not use for longer than 7 days at a time

other advice for hay fever?

-stay indoors when possible -don't let pets inside as they may bring in pollen -don't keep fresh flowers inside -shut windows during the night -Use sunglasses when outdoors -avoid trigger factors -Avoids parks and fields when pollen count is high

Development of allergic rhinitis

1. Sensitisation - APCs (e.g macrophages, dendritic cells) encounter allergens then engulf it producing an antigen complex which activated T&B cells with release of immunoglobulin E (IgE) by B cells. IgE attaches to the surface of mast cells 2. Early response - Release of mediators e.g histamine 3.Late response - complex inflammatory process with nasal congestion. Mediators involved include cytokines, prostacyclin and leukotrienes

Antihistamines - what are they and how do they work?

Antihistamines are H1 Receptor Antagonists Histamine is the major mediator released in rhinitis and it acts on H1 nasal receptors to induce symptoms of itching, rhinorrhoea and sneezing Antihistamines are COMPETITIVE ANTAGONISTS which prevent the action of histamine at H1 receptors. They surprise mucus production in the nasal mucosa thus relieving nasal symptoms such as runny nose, sneezing and post nasal drip that causes coughing. Little or no effect on nasal congestion

What other conditions may mimic the symptoms of hay fever?

Cold and flu symptoms e.g sneezing and runny nose The conditions include: persistent allergic rhinitis, non-allergic rhinitis, pregnancy, conjunctivitis, nasal foreign bodies or blockage

Treatment - oral 2nd generation antihistamines

Generally non-sedating -Cetirizine (bendryl, allacan) -Loratadine (Clarityn) _Acrivastine *Cetirizine may be more sedating than loratadine (equally effective)

Differential diagnosis with the common cold

Initial clear nasal discharge becomes thick within a few days Sneezing is less frequent No nasal itching No eye symptoms Contagious Gradual onset of symptoms and can occur any time of the year; usually winter

What does H1 and H2 do in an allergic reaction

H1 - vasodilation, pruritis, Smooth muscle contraction H2- increased contractility of heart

What is hayfever?

Hay fever is better described as seasonal allergic rginitis and is defined by the presence of sneezing attacks and nasal discharge and blockage for more than an hour on most days. (Limited period of the year → seasonal)

What non-prescription medicine would be most appropriate for this student?

Loratadine should be recommended as the first-line as it causes the least sedation and no drug interactions so it will not impact the student's performance.

what is the aetiology of hay fever?

Most common cause: Pollen from trees and grass (intermittent/seasonal hayfever)

Typical symptoms of hay fever?

Nasal irritation Sneezing Watery rhinorrhoea itchy eyes and nose

Non-prescription medicines

Newer, non-drowsy antihistamines that are less likely to make you feel sleepy such as cetirizine, loratadine and fexofenadine are recommended

What questions and observations would you make to confirm a diagnosis of hay fever?

Observations: a runny nose, red/itchy eyes, hives -Symptoms? -Have you taken any medications? -Have you had hayfever before? -The onset of symptoms, how long? -Allergies? -Do you have eczema or asthma?

Antihistamine nasal spray

Relieve nasal itchiness, rhinorrhoea, sneezing rapid onset of action - 15 mins e.g. Azelastine - used twice daily in adults and children over 5

Treatment - oral 1st generation antihistamines

SEDATING - will cause drowsiness -Chlorphenamine (Piriton) -Promethazine -Clemastine side effects: dry mouth constipation blurred vision urinary retention

When to refer?

Wheezing or shortness of breath - asthma? Ear ache or facial pain - sinusitis? Purulent discharge from the eye - infection? Blood in nasal discharge If no improvement after 7 days treatment with OTC medicines

Initial investigatory questions

Who is the client? Appearance of client? Age? Symptoms? how long? Actions already taken? Current medication? Is the patient wheezing? Other symptoms.g muscle pain (myalgia) may indicate influenza relieved by?

Aetiology

cause of disease

Eye symptoms

clear watery discharge dilation of conjunctival blood vessels causing redness itching which can be severe photophobia

Treatment - anti-inflammatory: Intranasal corticosteroids

e.g Beclometasone,fluticasone -Most effective treatment so use as first line -Local anti-inflammatory effect: reduce the no. of mast cells and basophils and block release of mediators -Delayed onset of action; max effect may take several days -start treatment 2-3 weeks before hay fever season and continue -May be used regularly as a prophylactic (preventer) -Relieves itching, sneezing, rhinorrhoea and nasal congestion -OTC for adults over 18. Max use 3 months

Paroxysmal sneezing

fits of sneezing

What is perennial allergic rhinitis?

if it is present throughout the year it is described as PERENNIAL, typically from allergens such as house-dust mites and pets. There is sensitivity to various components in the atmosphere, such as pollen, mould spores, dust and pollutants.

Rhinitus

inflammation of the nasal mucosa (inside of the nose)

pruritus

itching

Loratadine

loratadine selectively inhibits histamine H2 receptors and suppress many of the vascular effects of histamine. It has a quick onset of action and can be given to all patient groups.

Rhinorrhea

runny nose