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Allergic conjunctivitis — all kinds of misery

Allergic conjunctivitis — all kinds of misery

Dear Dr. K: My brother has vernal conjunctivitis and I have perennial allergic conjunctivitis. We both use the same eye drops but I seem to do a lot better than he does. What gives?

What gives is that you have a less severe condition than your brother. Let me explain. Allergic eye problems fall into four general types: seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), allergic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC).

IgE (the allergic protein), plays a role in all four, but in ARC and VKG T-lymphocytes (the allergic cells) also contribute to the mischief. (Unlike in the familiar “pink eye,” caused by a virus or bacteria and not by allergy.)

SAC is probably the most common and is seen at all ages and equally in males and females. It is caused by seasonal pollens: ragweed in Fall, trees in Spring and grasses in summer. It responds better to eye drops than to oral antihistamines. The eye drops most commonly used are topical antihistamines or mast-cell stabilizers (mast cells release histamine).

PAC is also very common with the same age and gender distribution as SAC. Because it is perennial, it is usually caused by pet dander allergy, but also by dust mite and mold allergy. It responds to the same treatments as SAC.

In both SAC and PAC, the most common symptom is itching, but the eyes also tear, burn and can turn red. The eyelids can swell, but this is usually caused by unrestrained rubbing of the eyes – especially in young children.

Luckily, AKC is an uncommon allergy as it can be quite severe and adversely affect vision. This one is more frequent in males and more common in middle age. Most of these patients have eczema, and the eye symptoms often wax and wane with their skin symptoms. There can also be eczema surrounding the eyes, as well as other body areas. The eyes itch and tear, but also tend to produce a mucus discharge. The inside of the eyelids – more on the lower lids than the uppers – develop little bumps.

Antihistamine and mast-cell stabilizer drops are helpful. In severe cases, steroid eye drops are sometimes used to gain control of the problem but should only be used short-term. Cyclosporine eye drops and tacrolimus ointment to the external lids are also of benefit. Both medicines work on the T-cell part of the inflammation.

VKC (just as AKC) is perennial but can worsen in Spring — hence the name vernal as in vernal equinox. Eyes itch and turn red. This redness tends to be greatest on the white part of the eye right next to the iris. As in AKC, the inside of the eyelids develops bumps, but these tend to be worse on the upper lids. The eyes tear and also produce a ropey mucus discharge. It is most common in males but at a younger age: pre-teen and teen. It is treated the same way as AKC.

… And now the cat story

… And now the cat story

“Spoiler” alert!

Between 5 and 10% of the human population has an allergy to cat. The major cat allergen is a protein called “Fel-D-1,” which is a protein in the cat’s saliva, sebaceous glands and genitourinary tract. Dried skin particles (dander) contain the protein, even though the protein is not part of the coat itself.

Female cats produce less Fel-D-1 than male cats. Light-colored cats make less than dark-colored cats. Long-haired cats give off less allergen into the environment than short-haired kitties because their long fur holds the protein against the skin.

The Fel-D-1 protein is a very tiny molecule which allows it to stay airborne for a very long time, which in turn makes it easy to inhale. The particles are also very sticky, making it easy for them to cling to furniture, carpet, drapes, bedding and walls — so sticky they can “hang around” six-to-eight months after a cat has left the premises. These particles can also be picked up by shoes and clothing and travel home to abodes that have never housed a cat.

Even “hairless” breeds groom themselves, so the protein ends up on their skin. The only allergic advantage of “hairless” cats is they don’t harbor other allergens such as pollen or dust mites. And even after washing cats, the levels of Fel-D-1 are back up to pre-bath levels within 24 hours.

Child in crisis — Epi-Hug more than affection

Child in crisis — Epi-Hug more than affection

Because of the burgeoning of allergic disorders, more and more children are requiring auto- injectors of epinephrine. These devices are used to stop severe allergic reactions or anaphylaxis.

If the device is required it is obviously at a time of crisis for both the child and the parent, which makes it more likely for mis-adventures to occur. Because it is life-critical that the medication be properly administered, it usually requires some form of child restraint.

Thus has evolved the concept of compassionate restraint known as “the epi-hug.”

The best site to administer the epinephrine is the top side of the child’s thigh. So, try to visualize this: one parent should sit and place the child on his or her lap, with the child sitting on one of that parent’s legs, while the parent’s other leg rests on top of the child’s knees, immobilizing the child’s legs.

The parent should use her non-dominant arm around the child’s back to hold and immobilize the child’s free arm. Have the child place his other arm in a “hug” around the back of the parent. The parent’s dominant arm is then free to use the auto-injector on the child’s thigh.

Trying to administer the epinephrine to a non-restrained or “bucking” child has led to countless episodes of partially administered doses, broken needles and even of the parent accidently being injected.

The advice of “practice makes perfect” applies. If you’ve rehearsed the epi-hug with the “trainer” injector before a true need, it will help ensure all goes well.

Not real common, or innocent

Not real common, or innocent

Food additives are often suspected as a possible culprit for allergic reactions. A recent study done at LSU proves otherwise; that is, they are rarely a cause.

Most food additives fall into one of seven categories: antioxidants, coloring, emulsifiers, flavorings, taste enhancers, preservatives or stabilizers. The three most common allergy troublemakers are two preservatives (sulfites and nitrites), and one taste enhancer (MSG – monosodium glutamate).

Next most common are the dyes: carmine (red) and tartrazine (yellow). Other culprits include the emulsifiers guar gum, the preservative Benzoates and the artificial sweetener aspartame.

Allergic manifestations of food additives can vary from asthmatic rhinitis, skin rash, gastro upset and headache. As there are no standardized skin or blood tests to diagnose food additive allergy, a more “seat-of-the-pants” approach is required, such as keeping a diet/adverse event diary, or doing an oral food challenge with the suspected culprit.

Quick Tips: Sjogren’s Syndrome

Quick Tips: Sjogren’s Syndrome

Another  recent study from that publication found that people with the chronic allergic “triad” of rhinitis, asthma and eczema have a much greater risk of developing Sjogren’s Syndrome (an auto-immune condition causing dry eyes and mouth) than the general population.

Celiac disease needs two genes and virus to switch on

Celiac disease needs two genes and virus to switch on

It has been known for some time that two HLA genes (DQ2, DQ8) predispose to celiac disease. What was recently discovered, and reported in The New England Journal of Medicine, is that is seems to take a virus to activate these genes that leads to the disease.  The research focused on the interplay between viruses and genes causing celiac disease, with its gluten sensitivity. The genes alone don’t cause celiac disease.

The virus that appears to be the culprit is a Reovirus that infects the intestines, but is otherwise innocuous, in that is doesn’t cause any symptoms or illness. But in people who inherited HLA-DQ2 or DQ8, the genes are “switched on” and the auto-immune gluten sensitivity develops.

This is very compelling research because development of a viral vaccine could prevent millions of cases of celiac disease.

Mighty mites proven peskier

Mighty mites proven peskier

Dust mites have long been known as the No. 1 cause for allergic asthma around the world. They are the “perfect respirable particle” – at only seven microns in size – and thus, easily inhaled into the lungs.

Based on this information it has long been assumed that the development of dust-mite allergy must occur via breathing in the particles.

Well, new research at the Pasteur Institute in Paris has found otherwise. It seems that the early development of dust-mite sensitivity occurs through the skin. This finding helps explain why many infants have eczema caused by dust-mite allergy, and then later develop allergic asthma.

The researchers in Paris found that dust mites are able to initiate this allergic immune response even in children with normal intact skin. Of course, once eczema develops, there is more ready penetration of the skin layers.

Based on this research it seems reasonable to work harder to minimize dust-mite exposure to infants. Good moves: use mite-barrier sheets, avoid stuffed animals and frequently wash sheets.