X hits on this document

82 views

0 shares

0 downloads

0 comments

21 / 33

as delayed wound healing, secondary infection, elevated intraocular pressure, and formation

of cataract. In addition, the anti-inflammatory and immunosuppressive effects are nonspecific. Corticosteroids exist in various forms and potencies. Relatively weak steroids such as rimexo- lone, medrysone, and fluorometholone tend to have lower potency with fewer ocular side effects. In contrast, agents such as prednisolone acetate are more potent and have a higher incidence of side effects. A relatively new steroid, loteprednol etabonate, is rapidly metaboli- zed once it enters the anterior chamber of the eye. Therefore, it is extremely useful in treating ocular surface and superficial corneal inflammations. It has a specific indication for ocular allergy and has been shown in clinical studies to have fewer ocular side effects. [9]

!

However, a general rule-of-thumb is that topical steroids should be prescribed only by oph- thalmologists for a short period of time and for severe cases that do not respond to conven- tional therapy.

Cyclosporine A This modality has been tried by some ophthalmologists. Cyclosporine A was approved for the treatment of keratoconjunctivitis sicca and may someday be a treatment option for allergic conjunctivitis. In some studies, it has been shown that man- agement of allergic conjunctivitis with topical cyclosporine A produced satisfactory results and patients experienced symptomatic relief within the first week of treatment. [10,11] In one study, Daniell and co-workers showed that topical cyclosporine A 0.05 % was not beneficial compared to placebo as a steroid sparing agent in steroid dependent allergic conjunctivitis. [12]

Immunotherapy This treatment modality is usually administered by immunoallergologists who are experienced with this kind of therapy. Immunotherapy can be beneficial in some patients with allergic conjunctivitis. [13] I m m u n o t h e r a p y , o r a l l e r g y s h o t s , i n v o l v e s i n j e c t i n g i n c r e a s i n g d o s e s o f t h e o f f e n d i n g a n t i g e n

or antigens in an attempt to attenuate the specific allergic response. An immunotherapy extract is prepared on the basis of skin-testing results. The patient then receives increasing doses subcutaneously on a weekly or twice-weekly schedule for about five months. After this so-called build-up phase, the patient is maintained on a stable dose that is administered weekly to monthly for several years. Usually, patients achieve maximal benefit after being on the maintenance dose for one year.

MEDICAL TREATMENTS THAT CAN BE USED BY THE GENERAL PRACTITIONER IN MANAGING DIFFERENT TYPES OF ALLERGIC CONJUNCTIVITIS

Seasonal and perennial allergic conjunctivitis Various classes of medication may be effective against the symptoms of acute allergic con- junctivitis; each is directed at a specific point in the inflammatory and allergic cascade. The following can be used:

  • Artificial tear substitutes

  • Topical antihistamines

  • Mast cell stabilisers

40

ALLERGIC CONJUNCTIVITIS

  • Dual action drugs

  • Vasoconstrictors

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)

Vernal keratoconjunctivitis V K C s h o u l d b e r e f e r r e d t o a n o p h t h a l m o l o g i s t a s t h e t h e r a p e u t i c o p t i o n s a r e m a n y , a n d

should be chosen on the basis of the severity of the disease. However, the general practitioner

as a start point can give the following:

  • Mucolytic agents such as acetylcysteine may help minimise the discharge and provide temporary relief.

  • Mast cell stabilisers are perhaps the mainstay of treatment of VKC and are safe for long- term use.

  • Oral aspirin as adjunctive therapy for intractable cases of vernal conjunctivitis has been shown to be effective. Aspirin acetylates the enzyme cyclooxygenase, thereby preventing the formation of prostaglandin D2. [14]

Referral to an ophthalmologist is mandatory to continue management with the following:

  • Topical steroids are the most effective drugs. They should be prescribed by an ophthal- mologist at the lowest effective concentration and for the shortest duration possible. A pulsed-therapy regimen is generally recommended such as 1 % prednisolone acetate every two hours for the first week followed by a rapid taper; this may be repeated if symptoms recur.

  • Systemic steroids may be used in severe cases, but generally are not necessary for mode- rate cases of VKC.

  • Topical 2 % cyclosporine A in castor oil should be considered as an alternative to steroids and may be effective in reducing some of the signs and symptoms of VKC without adver- se effects.

  • Treatment of corneal shield ulcer may require the use of antibiotic-steroid ointments.

Atopic keratoconjunctivitis Treatment of patients with AKC is similar to that of VKC and should be by an ophthalmologist. As with VKC, topical mast cell stabilisers and topical corticosteroids provide significant relief of symptoms. Mast cell stabilisers have to be used for several weeks prior to seeing a clinical effect, and in the interim, topical steroids used in a pulsed fashion may help to control symp-

toms. Systemic antihistamines that are specific for H1 histamine receptors have been found to be helpful. Systemic steroids are rarely required, except in cases of vision-threatening compli- cations. Systemic cyclosporine A, which has been shown to be effective in the treatment of atopic dermatitis, has shown promise in controlling ocular inflammation in AKC. [15] This tre- atment modality can only be performed by an immunology department.

Giant papillary conjunctivitis Treatment of patients with GPC is similar to that of AKC and VKC and should be by an oph- thalmologist. The goal of treatment in GPC is resolution of symptoms and restoration of functional use of contact lenses or ocular prosthetics. Although removal of the responsible foreign body is the definitive treatment, and while that may be appropriate for exposed sutures or scleral buckles,

ALLERGIC CONJUNCTIVITIS

41

Document info
Document views82
Page views82
Page last viewedFri Dec 09 22:13:51 UTC 2016
Pages33
Paragraphs1444
Words22306

Comments