spring conjunctivitis
Introduction
Introduction to spring conjunctivitis The more accurate name for spring conjunctivitis (vernalconjunctivitis) is spring keratoconjunctivitis (VKC), a bilateral chronic external eye disease in which atopic individuals can respond to antigens prevalent in the environment. The main diseases include eczema, asthma and urticaria. VKC mainly affects children and young adults. It is the most common in spring, so it is called spring conjunctivitis. The affected patients mainly show external eye diseases, the main symptoms. For itching, tears, shame and sticky secretions. The disease has "self-limiting", and currently available drugs have topical glucocorticoids and mast cell stabilizers. basic knowledge The proportion of sickness: 0.01% Susceptible people: no specific population Mode of infection: contact spread Complications: cataracts, keratitis, keratoconus
Cause
Cause of spring conjunctivitis
(1) Causes of the disease
The cause of the disease is unclear and may be related to atopy, with environmental and ethnic orientation.
(two) pathogenesis
VKC may involve more than one immunological mechanism. Direct and indirect evidence suggests that VKC may be a type I hypersensitivity (rapid-type, IgE-dependent allergic response), and patients often have a family history of atopy or atopy. The histamine level in tears is elevated. Histopathology shows that there are many degranulated mast cells in the parenchymal parenchyma and epithelial layer, which have a good therapeutic response to sodium cromoglycate. These facts suggest that VKC is a kind of IgE and hypertrophy. Cell-mediated immune processes, although difficult to identify specific virulence factors that trigger abnormally excessive inflammatory responses, skin tests often show that patients are sensitized to several ubiquitous environmental antigens, especially to house dust mites.
However, only type I hypersensitivity does not fully explain the histopathology of VKC. Studies of histopathology and immunopathology suggest that VKC may also be type I hypersensitivity (rapid hypersensitivity) and IV. Histopathological study of conjunctival nipples revealed a large number of hypersensitivity reactions (later-type or cell-mediated hypersensitivity reactions) in addition to allergic cells (mast cells and eosinophils) in the nipple. Monocytes, fibroblasts and newly secreted collagen, monocytes with helper (CD4) T cells, especially IL-2 secreting Th2 cells, and conjunctival epithelial cells and stromal cells HLA-II Increased expression of antigen.
Prevention
Spring conjunctivitis prevention
This disease belongs to the immune response caused by allergens stimulating the body, so the preventive measures should be carried out according to the cause. In the spring, especially in the spring and summer, due to the recovery of all things, avoid going to parks and other places containing more plants and flowers to avoid pollen allergies. Induces spring conjunctivitis. At the same time, we should actively seek and avoid contact with allergens, or perform desensitization after allergen examination, and can also avoid the occurrence of this disease.
Complication
Spring conjunctivitis complications Complications cataract corneal stroma inflammation keratoconus
Diseases associated with VKC include keratoconus and atopic cataracts, corneal ulcers, keratitis, spherical conjunctiva, and transparent edge degeneration.
Symptom
Symptoms of conjunctivitis in the spring Common symptoms Itching, tears, conjunctiva, grayish white membrane, conjunctiva, huge nipple, wind, tears, ptosis, conjunctival hyperemia, nipple hypertrophy, keratitis, conjunctival nipple hyperplasia
VKC is characterized by a large nipple on the bilateral conjunctiva, but sometimes it also appears in the conjunctiva of the limbus. The main symptom is persistent itching, after various stimuli or induced environment during the day, such as dust. Dandruff, light, wind, perspiration and rubbing, tend to worsen at night, other symptoms are pain, foreign body sensation, shame, burning sensation, tearing and sticky secretions. The variability of symptoms is the main feature of VKC in the early days. As the disease progresses, the symptoms gradually worsen. In some cases, it is perennial. In 1888, Emmert divided VKC into eyelid type, corneosclear type and mixed type, but it is sometimes difficult to classify it into a certain type in a certain case. Therefore, considering VKC may have more important classification significance depending on the severity of the symptoms and the clinical changes that attach importance to the affected tissue.
1. Conjunctival changes The conjunctiva and bulbar conjunctiva are the main affected parts of VKC. The palpebral nipple reaction occurs in the upper conjunctiva. The nipple sometimes fuses. These nipples are polygonal, with flat head and naked eyes. The examination is clearly visible. However, these nipples are not disease-specific. The nipples are visible under the slit lamp with diameters of 1 to 8 mm, which are connected to each other. Each nipple has a central blood vessel, and fluorescein can stain the top of the nipple. There is often a layer of sticky milky white secretion on the surface and a viscous pseudomembrane, and no follicular reaction is observed in the affected conjunctival area.
The change of the limbus is mostly caused by colored people, mainly characterized by glia-like nodules or ridges in the limbal limbus, mostly located in the upper 1/2 of the limbeosalma, and small white spots called The Horner-Trantas point is mainly composed of inflammatory cells of eosinophils, and sometimes the thinning, widening and turbidity of the conjunctiva in the limbus is observed.
2. Changes in the cornea In patients with VKC, the degree of corneal involvement can be used as an indication of the severity of the disease. In patients with orbital VKC, up to 50% of cases have corneal pathology, and patients with orbital or mixed VKC are almost no exceptions. There are complications of the cornea in the ground.
Epithelial keratitis is a common corneal manifestation, mainly characterized by the presence of spotted dark gray turbidity on the cornea 1/2, like dusty, these punctate opacity can be broken and merged to form a large erosion, these erosions The base is shallow and the edges are raised, forming a dense layer of cell debris and mucus, called the vernal plaque, sometimes called the "shield ulcer," which usually only occurs in younger The patient, often located above the cornea, has a transverse elliptical shape. The ulcer area often inhibits normal re-epithelialization. Therefore, the healing of the erosion area is very slow, often resulting in permanent, gray, elliptical epithelial opacity. These corneal plaques are very Less vascularization occurs unless chronic inflammation occurs, but these ulcers are at risk of developing secondary microbial infections, resulting in permanent corneal sequelae.
Matrix type keratitis can also occur in patients with VKC. The most common corneal degeneration change is a pseudo old age ring, similar to the old ring. This curved surface matrix turbidity is mainly located in the peripheral part of the cornea, often between the opacity area and the limbus There is a transparent area with spaces. In some cases, this focal yellow-gray opacity sometimes causes ulceration, causing peripheral thinning of the groove. Further changes will lead to myopic astigmatism. The pseudo-elderly ring is often accompanied by new blood vessels. Enter the peripheral part of the cornea to form a vasospasm above the cornea.
3. Changes in the external eye The eyelids may also have some signs of VKC. Common signs include ptosis, which may be related to the increase in eyelid weight caused by secondary spring nipple hypertrophy. Sometimes excessive wrinkles in the lower jaw skin may be observed. Pleats (Dennie line).
Examine
Examination of spring conjunctivitis
The diagnosis of a typical VKC is very easy, but it is difficult for some atypical cases. The following tests and examinations may be helpful for diagnosis. Allergic tests can be used for atopic or systemic allergic diseases, sometimes Can also be used in patients with refractory VKC.
1. Conjunctival cytology conjunctival scraping is helpful for the diagnosis of allergic eye disease. Normal human conjunctiva does not contain eosinophils or eosinophilic granules. Therefore, eosinophils or eosinophils are found in Giemsa staining of conjunctival scrapings. Acidic particles will suggest local allergic processes, and the conjunctival biopsy tissue will have mast cells, basophils, eosinophils and/or eosinophil granules under electron microscope, and have the same clinical value. Mast cells and their granules can be identified and counted by electron microscopy. In patients with VKC, many mast cells undergo extensive degranulation, making them difficult to identify under light microscopy.
2. Composition of tears The change of tears has important clinical significance. The number of eosinophils, neutrophils or lymphocytes in tears increases, suggesting an allergic state. In patients with allergic eye diseases, occasionally it is detected. The level of histamine is elevated, but this increase is not present in patients with VKC, and the level of IgE in serum and tears of patients with VKC is higher than normal.
The level of tryptase in tears can reflect the extent to which mast cells participate in allergic eye diseases. For normal people, patients with VKC, other allergic eye diseases or non-allergic inflammatory diseases, tear-tryptase is not stimulated. The level of detection was also tested. The changes of tear tryptase levels in common allergens, instilled with compound 48/80 or blinking, and the levels of non-irritating tear-like tryptase in patients with allergic eye disease were also observed. Increased, while atopic individuals use allergens and compounds 48/80 in the eye, or normal individuals showed only a slight increase after compound 48/80 stimulation and rubbing trauma, tryptase is a disease involving mast cells The precursor to the process, therefore, its level can be used as a useful indicator of mast cells involved in spring conjunctivitis and other allergic eye diseases.
In patients with dry keratoconjunctivitis, the concentrations of lacrimal lactoferrin and lysozyme decreased, and the concentration of lactoferrin in the tears of patients with VKC or giant papillary conjunctivitis (GPC) decreased, but the level of lysozyme remained normal. The decline in protein and the normal deviation pattern of lysozyme may be a unique phenomenon of VKC and GPC, the reason for which needs further study.
VKC is a proliferative disease in nature, characterized by increased formation of transparent connective tissue. In the conjunctiva, hypertrophic nipples are covered with proliferating epithelial cells, and the number of goblet cells is increased. Each nipple has a central vascular bundle. The central blood vessels are surrounded by edema tissue infiltrated by inflammatory cells. The infiltrating cells are mainly plasma cells, eosinophils, mast cells and lymphocytes. The active phagocytosis of tissue cells and neutrophils can be observed at the corner. In the scleral margin, the conjunctival epithelium and subepithelial fibrovascular connective tissue proliferate and are infiltrated by several kinds of cells, resulting in the formation of glial nodules. Some Homer-Trantas nodules in the affected limbus are rich in eosinophils. .
Eosinophil degeneration, connective tissue transparency and parenchymal neovascularization will eventually lead to edema and proliferation of capillary endothelial cells, with up to 10 layers of ede epithelial cells on the nipple, and spheres in the limbus The conjunctiva is more than 30 to 40 layers, and the conjunctival epithelial layer is thinned at the top of the nipple, which is somewhat colored.
It is generally believed that the corneal manifestation of VKC is caused by the friction of the conjunctiva, but the chemical toxicity caused by the degranulation of mast cells and eosinophils is also an important factor for corneal changes. Under normal circumstances, mast cells are located in the parenchyma of the conjunctiva, in the spring. In conjunctivitis, mast cells can occur in the affected conjunctival epithelium and degranulate, and degeneration and shedding of corneal epithelial cells can cause punctate keratopathy.
Immunohistochemical analysis showed that there were a large number of helper T cells in the conjunctiva, the ratio of helper T cells/inhibitory T cells (CD4/CD8) was reversed, and a large number of Langerhans cells were contained. The conjunctiva in the affected area contained many secretory IgE. Plasma cells, many activated T cells express CD25 (IL-2 receptor), and -IFN and other cytokines secreted by these immunocompetent cells can induce epithelial cells to express HLA-II antigens, which are large in the VKC conjunctiva. Most T cells belong to Th2 type cells and can produce IL-4 which is involved in IgE synthesis. IL-4 is a growth factor of mast cells and B cells. Therefore, Th2 type cells may promote the aggregation of mast cells and B cells in the VKC conjunctiva. .
Diagnosis
Diagnosis and identification of spring conjunctivitis
Diagnostic criteria
According to VKC, it is a bilateral conjunctival chronic inflammation with seasonality, which is more common in children and young people. The characteristics of pubertal lesions begin to subside, and combine with the typical features of VKC, the giant nipple of the bilateral conjunctiva. The diagnosis can be basically confirmed. The main symptoms of the disease are persistent itching, and the symptoms are aggravated at night. The signs should be checked for the clinical diagnosis of the common lesions of the palpebral conjunctiva, the corneoscleral margin and the cornea.
VKC should be differentiated from other allergic conjunctival diseases. Patients with severe VKC have typical signs: palpebral conjunctival palisade-like papillary hyperplasia, shield-shaped ulcer, Horner-Trantas point, and other signs. However, for mild cases, diagnosis is difficult. Laboratory tests are often required.
Differential diagnosis
1. Atopic keratoconjunctivitis (AKC) In the early stage, the two diseases are often confused. In epidemiology, AKC occurs mostly in the teens to middle age; mostly perennial, longer than the VKC course From the outside, AKC patients often have chronic eyelid inflammation and eczema in their eyelids. Unlike VKC, AKC often causes conjunctival scarring, subepithelial infiltration and narrowing of the inferior collapsium. Other symptoms and signs also help to distinguish between the two. : AKC mainly affects the lower conjunctiva and has small nipples; the corneal neovascularization of AKC is usually located in the deep layer; the secretion of AKC is mostly watery, while the secretion of VKC is mostly viscous; it is difficult to find Homer-Trantas in AKC. Point; AKC conjunctival scrapings are rarely found in eosinophilic particles.
2. Herbaceous thermal conjunctivitis, also known as seasonal allergic conjunctivitis (SAC), is a common clinical disease. It rapidly develops after contact with antigen, mainly characterized by conjunctival hyperemia, conjunctival edema and occasional eyelid edema. Unlike VKC, SAC patients are often accompanied by allergic rhinitis or sinusitis, and corneal changes are difficult to observe in SAC.
3. Giant papillary conjunctivitis is mainly related to wearing contact lenses. Other stimulating factors include wearing artificial eyes and burying sutures. The nipple reaction and mucus production of the upper conjunctiva are very similar to VKC. The symptoms and signs of GPC will be significantly reduced or disappeared, and differential diagnosis can be performed by medical history analysis and careful examination.
4. Contactive conjunctivitis Chemical (or toxic) conjunctivitis caused by the use of drugs to induce hypersensitivity reactions can also produce symptoms and signs similar to VKC, the main drugs causing drug hypersensitivity reactions are: atropine, local anesthetics, Antibiotics, phenylephrine and other drug carriers, chemical conjunctivitis nipple reaction is not severe, the lower iliac conjunctiva is susceptible.
5. Trachoma trachoma can also cause pathological changes above the conjunctiva and the corneoscleral margin. However, unlike VKC, trachoma can cause conjunctival scarring, follicular conjunctivitis and Arlt line (horizontal subepithelial fibrosis), conjunctiva The scraper has no eosinophils present, however, VKC sometimes exists simultaneously with trachoma.
