Can Hay Fever Be Prevented?

There was a study in the ear, nose, and throat field comparing when to start antihistamines for Japanese cedar pollinosis (preventive dosing before pollen release, or early dosing after onset).¹。

Even when levocetirizine (an antihistamine) was started early after symptoms appeared, it suppressed allergic rhinitis symptoms about as well as preventive use before pollen release. Because it is not necessarily required to start before release, this result is considered important in terms of both comfort of life and reducing medical costs.¹。

Hay fever is the “seasonal” type of allergic conjunctivitis.

Itching is caused by a chemical called “histamine.”

Antihistamine eye drops
prevent the “mast cells” in the conjunctiva from rupturing and releasing histamine.
Alesion^®• Patanol^®• Intal^®• Livostin^®• Rizaben^®eye drops, and others
Hay fever and dry eye

Starting eye drops before pollen is released (“preventive treatment”) is not mentioned in the Japanese Ophthalmological Society’s guideline on allergic conjunctival disease².

Immunologically, rhinitis and conjunctivitis share the same mechanism (why they occur), so I believe preventive treatment for Japanese cedar pollinosis is effective.

The following is based on the Japanese Ophthalmological Society’s Guidelines for the Clinical Management of Allergic Conjunctival Disease (2nd edition).
Please use it as a reference for prevention (self-care).

For treatment,
○ Use of antihistamines
○ Use of steroids (adjusting the eye drop concentration)
○ Evaluation for dry eye
are the main pillars,

and for strong inflammation (vernal keratoconjunctivitis),
○ Immunosuppressant eye drops
○ Subtarsal injection of a steroid suspension (Kenacort)
are used.

Allergic conjunctivitis
The surface of the eye is in contact with the outside world, so all kinds of things can get in and cause inflammation.
The most common is pollen.
　Japanese cedar, Japanese cypress, rice, ragweed, mugwort, and more

Dust mites and house dust can also be causes.
Contact lenses also touch the surface of the eye, so they can cause allergic inflammation.

Symptoms
Itching, redness, sneezing, runny nose, nasal congestion, eye discharge, tearing, foreign-body sensation (gritty feeling), skin itching (itchy eyelids), eye pain, eyelid swelling, visual disturbance (difficulty seeing), throat itching

In the eye clinic, we turn the eyelid over and observe the conjunctiva:
• Redness, swelling, bumpiness (follicles and papillae), edema (fluid leaked from blood vessels by inflammation), and more

If the inflammation is very strong, damage to the black of the eye (cornea) touching the eyelid may be seen.
Swelling at the border between the black and white of the eye (limbus) (Trantas dots): seen at the corneal limbus, where immune reactions are strong, in the intense allergic inflammation of “vernal keratoconjunctivitis.”

Seasonal → “Hay fever” (seasonal allergic conjunctivitis)
Non-seasonal → “Allergic conjunctivitis due to dust mites and house dust” (perennial allergic conjunctivitis), “allergic conjunctivitis associated with atopic dermatitis” (atopic keratoconjunctivitis)

In allergy to contact lenses, the bumps on the inside of the eyelid can be very pronounced (giant papillary conjunctivitis).

Prevention (self-care): “Avoid exposure to the antigen as much as possible”

1. Removing indoor dust mites
　Bedding measures
　Using an air purifier
　Using a household vacuum cleaner

2. Fungi (mold)
　Dehumidifying,
　ventilating in summer,
　taking steps to avoid condensation in winter
　Avoid, as much as possible, carpets, tatami, cloth-covered walls, sofas, and other things where dust easily collects

3. Pollen
○ Use pollen information (Fukuoka Prefecture edition / Kyushu prefectures edition)
https://cgi.fukuoka.med.or.jp/kafun/kafun.htm
○ Glasses: even ordinary glasses alone can reduce the amount of pollen reaching the surface of the eye
○ Contact lenses → stop wearing them if possible and switch to glasses
○ Wash your eyes: with artificial tear eye drops!
　I do not recommend eye-wash cups:
　✔ They can push antigen stuck on the skin onto the surface of the eye
　✔ They contain high concentrations of preservatives
　✔ They can also wash away the good components in the tears
○ Cool your eyelids with a wet towel or similar
○ Clothing when going out: choose coats made of slippery fabric, and take them off before entering the house, and so on
　Do not bring pollen indoors

(References)
1. Yonekura, S., Okamoto, Y., Yamamoto, H., Sakurai, T., Iinuma, T., Sakurai, D., Hanazawa, T., 2013. Randomized Double-Blind Study of Prophylactic Treatment with an Antihistamine for Seasonal Allergic Rhinitis. IAA 162, 71–78. https://doi.org/10.1159/000350926
2. Guidelines for the Clinical Management of Allergic Conjunctival Disease (2nd edition), Journal of the Japanese Ophthalmological Society 114(10), 829-870, 2010-10-10