Dousing the Flames of Allergic Eye Disease
Transcription
Dousing the Flames of Allergic Eye Disease
The College of Optometrists Optometry Tomorrow 2011 Dousing the Flames of Allergic Eye Disease Dr Robert Harvey Consultant Ophthalmologist at Royal Alexandra Hospital, Paisley, Scotland. Plan • • • • A bit of theory – immunology Diagnosing allergy – usually easy Rationale of treatment Risks and benefits of treatments New Paradigm POM Prescription Only Medicine P Pharmacy only GSL General Sale List R Prescription only OTC Over The Counter Certificate of European conformity China Export Immune Reactions • Type I Hypersensitivity Reactions – Atopic diseases • Type II Hypersensitivity Reactions – Antibody cytotoxic effect • Type III Hypersensitivity Reactions – Immune complex diseases • Type IV Hypersensitivity Reactions – Delayed cell mediated hypersensitivity Type I Hypersensitivity Reactions Atopic diseases • IgE / mast cell mediated histamine release. • Disease entities include: allergic conjunctivitis, atopic dermatitis, latex allergy and extrinsic asthma. Type II Hypersensitivity Reaction Antibody cytotoxic effect • Cell injury • Disease entities include: Incompatible blood transfusions anti-A and Anti-B antibodies directly bind complement leading to rapid haemolysis. • In Graves' disease an antibody to the thyroid stimulating hormone (TSH) receptor occurs that simulates the effect of TSH on its receptor thereby causing hyperthyroidism. • In myasthenia gravis antibodies to the acetylcholine receptor occurs and in pregnancy 20% of mothers have an infant affected by neonatal MG for 3 weeks. This is a transient myasthenia due to the transplacental transfer of antibodies. Type III Hypersensitivity Reactions Immune complex diseases • 1) Vasculitis; 2) Arthus reaction (localised rapid skin reaction); 3) Serum sickness due to serum, drugs, or viral hepatitis • Disease entities include SLE; RA; polyarteritis; acute glomerulonephritis. • Diagnosis may depend on finding circulating antigen, (e.g. altered IgG (rheumatoid factor), or • Measuring complement levels ( total or early components (C1, C4, or C2). Depressed levels indicate a classic complement activation and therefore a type III reaction. Type IV Hypersensitivity Reactions Delayed cell mediated hypersensitivity • Memory cells (primarily T cells and macrophages) cause a later (secondary) cellular response. • Response appears 48 to 72 hours after antigen exposure. • Disease entities include contact dermatitis,, granulomas due to intracellular organisms like Tuberculosis, • Late graft rejection e.g. penetrating corneal graft rejection. Types of Allergic Conjunctivitis • SEASONAL ALLERGIC • VERNAL KERATOCONJUNCTIVITIS • ATOPIC KERATOCONJUNCTIVITIS • GIANT PAPILLARY CONJUNCTIVITIS • CONTACT ALLERGY Type I • • • • • Hypersensitivity Reactions Atopic diseases The main players are quite simple… Immunoglobulin IgE Mast cells Eosinophils Histamine • The intended effect is protection of the host from external threats. The protection itself needs regulation (homeostasis). Immunoglobulin E IgE • IgE production by B cell lymphocytes (plama cells) • Y shaped molecule with two arms (antigen detection) and a functional end to trigger an effect FC receptor (attaches to the mast cell). IgE • Hyper variable region • Hinge region Mast cell • Fc region Lymphocytes Mainly either T cells or B cells T cells have a role in detection and control. Cell mediated immunity B cells responsible for antibody production Cytokines Plasma cell Antigen presenting cell Dendritic cell Langerhans cell Found in the cornea and mucous membranes MALT Mucous membrane assoc lymphatic tissue APC - antigen processing • Birkbeck granules within Langerhan’s cell Eosinophils • Granules stain with the acidic dye eosin which is pink. • Granules, contain histamine and proteins eosinophil peroxidase, RNase, DNases, lipase, plasminogen, and Major Basic Protein. • Chemicals released by degranulation following activation of the eosinophil, (toxic to both parasite and host tissues). • Useful in dealing with parasites like hookworm infestation – not much use with hayfever! Mast cell Granules contain histamine and heparin. Degranulating Mast Cell Histamine causes vasodilatation and increased vascular permeability Allergy SENSITISATION Intervene by blocking the pathway at various steps REACTION Pollen Grains Grass pollen Scots pine Golden rod Pollen chart Early season Extended season Wimbledon Glorious 12th August Grass pollen - Hayfever Not just pollen House Dust Mite Iatrogenic • Chronic (neomycin) • Acute allergy Management HISTORY • New soap, shampoo, hair dye, lash tinting. handling chemicals, occupation / gardening Any contact with feathers, animal danders. Contact lens wear, cleaning solutions, eye drops, • Duration, days, weeks… • Intensity • Other known allergies • Use of antihistamines • Reconsider diagnosis e.g. possible infection with adenovirus… Presentation of Allergic Conjunctivitis COMMON CHARACTERISTICS: BILATERAL itching, Pale milky conjunctiva, Ropy mucoid discharge, Papillary hypertrophy of conjunctiva, also nasal symptoms. SEASONAL ALLERGIC CONJUNCTIVITIS SAC • Commonest, hypersensitivity to airborne allergens (pollens) Hayfever • Perennial if secondary to house dust mite or animal dander • Nasal symptoms are common, as is atopy • Itchy, red, watery eyes with milky conjunctiva and puffy lids. • Conjunctival chemosis. SAC • • • • PATHOLOGY Biphasic response Mast cells degranulate causing histamine release Esosinophils recruited causing a second wave of histamine release. • INVESTIGATION • Conjunctival scraping = >1 eosinophil on Giemsa stain • TREATMENT • Avoid allergens / pollens • In Britain the pollen count rises in summer to very high levels particularly on hot windy days. The pollen source varies according to season… • During the spring (March to May) generally tree pollen • From May to July mainly grass pollen • In the autumn months weeds such as nettles and docks, late flowering plants and mould spores. Rx Seasonal Allergic Conjunctivitis • • • • Normal saline irrigation. Topical mast cell stabilisers (safe). Topical / systemic antihistamines. Topical NSAID (synergistic effect with antihistamines). Short term use only. • Desensitisation treatment (ironically increases serum antibody level). Topical mast cell stabilisers • Disodium cromoglycate, Opticrom ™ 4 x day. Off-patent - readily availalable. • Olapatadine Opatanol ™ 2 x day • Nedocromil Rapitil ™ 2 x • Lodoxamide Alomide ™ 4 x Topical Antihistamines • LODOXAMIDE Alomide ™ 0.1% solution allergic conjunctivitis or vernal keratoconjunctivitis. (preservative: BZK). 4 x age over 4 yrs • AZELASTINE Optilast ™ allergic conjunctivitis 2 x • LEVOCABASTINE Livostin ™ allergic conjunctivitis • ANTAZOLINE Otrivine-antistin ™ allergic conjunctivitis. Also contains xylometazoline (a vasoconstrictor - temporarily whitens the eye, but later rebound redness). 2-3 x • EMEDASTINE Emadine ™. (preservative: BZK). Potent H1 antagonist Side effects include local irritation, pruritis, erythema, chemosis, blurred vision. 2 x, age over 3 yrs • OLAPATADINE Opatanol ™ 2 x day • 2 x age over 3 years (has a dual effect) SYSTEMIC ANTIHISTAMINES • SYSTEMIC ANTIHISTAMINES: • Older generation May cause drowsiness. Can be useful especially if itching is a problem at night. Potentiation of sedation in combination with alcohol or other sedating drugs. Risk of dry mouth, angle closure glaucoma due to anticholinergic side effects. • CHLORPHENIRAMINE Piriton ™ tabs or syrup. Adults 4 mg tablets (max 6 per day) • CLEMASTINE Tavegil ™ Adults 1 mg tablets, 1 twice daily (max 6 per day). Children over 1 yr 250mcg twice daily. • PROMETHAZINE Phenergan ™ Also available as iv injection 25 - 50 mg (given slowly) for use in anaphylaxis after adrenaline. Newer generation Anti-Hist • Do not cause drowsiness. Especially useful if there is a need to stay awake, drive etc. • CETIRIZINE (non-propr) 10 mg tab once daily • LORATADINE Clarityn ™ 10 mg tab. Not so good for relieving itchy skin as the sedating antihistamines. • DESLORATADINE Neoclarityn ™ or Aerius ™ 5 mg tab. Long acting up to 24 hours. Max 2 per day. Non-Steroidal Anti-Inflammatories NSAI • Topical NSAID (synergistic effect with antihistamines). For short term use only. • E.g. Ketorolac trometamol (Acular) ™ Used 3 x day. • Or Diclofenac (Voltarol) ™ • CAUTION • NSAIs have a local anaesthetic action so beware abuse which can result in neurotrophic keratitis (ULCER FORMATION). Topical steroids • • • • Effective but…. Risk of causing steroid induced glaucoma Risk of cataract Reactivation of Herpes simplex causing large geographical ulcer. Systemic steroids • Effective but there are also SYSTEMIC SIDE EFFECTS… • • • • • • • • • • • • • 1. Decreased wound healing, gastric ulcers, 2. Endocrine effects :- hyperglycaemia, 3. Hypertension, fluid retention, hypokalaemia, 4. Osteoporosis, bone fractures, vertebral collapse 5. Adrenal suppression leading to possible shock, 6. Weight gain 7. Infections- candida and herpetic 8. Psychiatric- florid in 10% on high doses, elation / depressn. 9. Avascular necrosis head of femur 10. Raised intracranial pressure (ICP) 11. Warn patients of the risk of generalised Varicella 12. Reactivation of Tuberculosis. 13. Steroid myopathy Rationale SENSITISATION REACTION Rationale Rationale Rationale SENSITISATION REACTION Inflammation may produce a positive feedback loop so the reaction becomes progressively more intense due to recruitment of more inflammatory cells and the release of more mediators. CORTICOSTEROIDS STEROIDS can interrupt the inflammatory process LEUKOTRIENE ANTAGONISTS • Montelukast Singulair ™ • Montelukast blocks leukotriene receptors. • DOSAGE • Montelukast 10 mg once daily in the evening regularly (can be used over age 15 years). • INDICATIONS • Asthma in addition to standard treatment when steroids and bronchodilators are not fully effective. • Hay-fever to relieve nasal congestion and sneezing and epiphora. VERNAL KERATOCONJUNCTIVITIS Vernal Catarrh VKC • Rare, 7-14 years (eventually self-limiting) Lasts up to 10 years • M>F • Bilateral, seasonal and recurrent • Commoner in warm climates • 50% atopic VERNAL KC • CLINICAL • Palpebral commoner in whites; limbal type commoner in blacks • SYMPTOMS • include itching, gritty, photophobia, excessive mucus • CONJUNCTIVA • Eosinophils ++ in conjunctival scrape. Vernal KC • Giant papillae Cobblestones upper tarsus (Polygonal, > 1 mm), • +/-Pseudomembrane Vernal KC - Corneal changes • Limbal papillae • “limbitis” • Trantas´ dots (Horner-Trantas' dots) are small white elevated spots due to esosinophil clumping/ concretions Vernal KC - severe • Superior punctate epithelial erosions, micropannus, • Shield ulcer, Mucous plaque, pseudogerontoxin (superior arcus). Rx - Vernal KC • Topical mast cell stabilisers (regular application). • Topical / systemic antihistamines • Topical steroids for a few weeks then slowly reduce frequency and strength). ATOPIC KERATOCONJUNCTIVITIS • M>F, • 30-50yrs (not self limiting) • Associated with atopic dermatitis • • • • • • FEATURES Bilateral, red, itchy eyes with copious discharge Blepharitis and lid dermatitis Thickened conjunctiva inferior tarsus Limbal papillae Trantas' dots +/-, AKS • Punctate epithelial erosions +/- pannus, • HSV and Staphylococcus infections are common • Increased frequency of cataracts (anterior subcapsular ops) or steroid induced post subcapsular lens ops, • +/- Ectropion • Incr incidence of keratoconus is linked to atopy. Rx Atopic KC • TREATMENT • Lid hygiene and hot compresses … • As for vernal KC + steroid cream to lids (watch IOPs), • Topical antibiotic • Treat rosacea with oral tetracycline or doxycycline • Cataract surgery when, if required. Giant Papillary Conjunctivitis. • Giant Papillae are over 1mm in diameter. • (VKC have extreme giant papillae with flat tops “cobblestones”). • Associated with foreign body e.g. contact lenses or protruding suture material Contact Allergy • Chemosis, hyperaemia, Conjunctival papillae, lid skin dermatitis. • Delayed hypersensitivity reaction. • TREATMENT • Stop the allergen! • ? Steroids as required to hasten resolution. Photo from Practical Ophthalmology Red Eye due to eye Rx • Drops for various eye conditions may cause conjunctival hyperaemia: • Prostas: Lumigan > Travatan > Xalatan • CAI: Trusopt or Azopt • Preservatives e.g. lubricants for dry eyes Lanolin even in lacrilube. • Allergies to antibiotics: chloram, neomycin Stevens Johnson Syndrome Acute inflammatory vesiculobullous reaction of skin and mucous membranes EM MAJOR Skin lesions + 2 or more mucous membranes Systemic toxicity Lasts 6 weeks • • • EM MINOR Skin involvement +/- 1 mucous membrane Lasts 4 weeks M = F, <30 years CAUSE Infections- HSV, Mycoplasma pneumoniae, virus, bacteria, fungi Drugs- sulphonamides, penicillin, salicylate, phenytoin, barbiturates. Vaccines, Collagen vascular diseases • • PATHOGENESIS Circulating immune complexes deposit at dermal-epidermal junction causing vasculitis • • • CLINICAL 1. prodrome - malaise, fever, headache, URTI 2. rash - target lesions, vesicles, bullae, extremities > trunk 3. mucous membranes conjunctiva (60%), mouth (100%), genitalia • Ocular Effects of SJS • Conjunctivitis or pseudomembranous conjunctivitis, • Scarring, symblephara (tethering of the conjunctiva to form bands). ankyloblephara (fusing of sections of the upper and lower lid margins). • Dry eye syndrome, entropion, trichiasis, corneal exposure, lagophthalmos. Photos from Practical Ophthalmology LIGNEOUS CONJUNCTIVITIS • Rare bilateral idiopathic chronic conjunctivitis occurring in children. • Acute onset, fibrinous exudate, • White membrane affecting upper tarsus. • May affect vagina and mouth. • • • • • • • TREATMENT Topical steroids, Ciclosporin, Mucolytics, Hyaluronidase, alpha chymotrypsin, Heparin. Sonja Klebe Br J Ophthalmol1999;83:878 Thank You More information on Interactive CD-ROM Email: [email protected] Practical Ophthalmology 1993 to 2011