|Year : 2014 | Volume
| Issue : 2 | Page : 65-70
Vernal keratoconjunctivitis in Jos, North-Central Nigeria: A hospital-based study
Keziah N. Malu
Department of Ophthalmology, Benue State University Teaching Hospital, Makurdi, Benue State, Nigeria
|Date of Web Publication||13-Jun-2014|
Keziah N. Malu
Department of Ophthalmology, Benue State University Teaching Hospital, Makurdi 102131, Benue State
Source of Support: None, Conflict of Interest: None
Background: Vernal keratoconjunctivitis (VKC) is a chronic, seasonally recurrent bilateral external ocular allergic inflammatory condition in response to allergens. It is more prevalent in the warm and dry tropical and subtropical climates of Africa, Middle East, Latin America, Asia (Indian Sub-Continent). VKC is a self-limiting disorder with spontaneous resolution after puberty or early adult life with male preponderance. The purpose of the study is to determine the prevalence and clinical presentation of VKC in a hospital clinic in Jos, Plateau State, North-Central Nigeria. Materials and Methods: This is a retrospective hospital-based study of patients seen with clinical diagnosis of VKC from 2000 to 2009 at Adoose Specialist Hospital, Jos, Nigeria. Results: The mean age of presentation was 14.6 ± 12.0 years while 62.8% were 16 years or younger, and 55% were male. Most of the patients had hyperpigmentation of the conjunctiva. The prevalence of the limbal (46.5%) and mixed (45.7%) subtypes of VKC were almost equal. The most frequently associated ocular conditions were refractive error (6.7%) and eye lid disorders (3.3%). Keratopathy was present in 2.2% patients with one case of keratoconus. Systemic allergic associations were rare. Conclusion: Clinical presentation of VKC in these patients is similar to those in other African countries and systemic associations were rare.
Keywords: Vernal keratoconjunctivitis, prevalence, pattern
|How to cite this article:|
Malu KN. Vernal keratoconjunctivitis in Jos, North-Central Nigeria: A hospital-based study. Sahel Med J 2014;17:65-70
| Introduction|| |
Vernal keratoconjunctivitis (VKC) is a chronic, seasonally recurrent bilateral external ocular allergic inflammatory condition in response to allergens. It is more prevalent in the warm and dry tropical and subtropical climates of Africa, The Middle East, Latin America, and Asia (Indian Sub-Continent) than in Western Europe and North America. ,,,,,, It is an important cause of hospital attendance in these regions, but rarer in Western Europe and North America.  Vernal keratoconjunctivitis is associated with symptoms of severe itching, watering or mucoid discharge, photophobia, foreign body sensation, burning and redness or brownness of the eyes. Common signs include bilateral palpebral (upper tarsal) conjunctival giant papillae (cobblestone appearance) and/or bulbar conjunctivallimbal giant papillary infiltration with a gelatinous hypertrophy of eosinophils and epithelial debris (Horner-Trantas Dots), conjunctival hyperpigmentation andhyperaemia, corneal keratopathy (superficial keratitis, and/or corneal shield ulcers) and pigmentary eyelid changes.
Patients with VKC usually present with a personal or family history of other atopic diseases, including allergic dermatitis, rhinitis, and asthma. It mainly affects children between the age of 3 and 16 years. It is a self-limiting disorder with spontaneous resolution after puberty or early adult life. Before puberty more boys are affected than girls.  There is hardly any gender difference after puberty.
In VKC both type I IgE-mediated and type II hypersensitivity reactions are active with cell-mediated Th-2 involvement of mast cells, lymphocytes and eosinophils. Several risk factors including genetics, socioeconomic, environmental factors have been implicated. Although VKC is a self-limiting disease a few patients end up with sight-threatening complications.  In Africa, population based studies showed prevalence rates of 4-5% in children, while 33-90% of children and adolescents attending hospital has VKC. ,,
Studies in Asia and Europe showed that boys are affected more significantly than girls, but in African case studies the sex pattern is varied. Gender differences in VKC usually becomes less with aging. ,,,
The limbal (bulbar) and mixed forms of VKC are seen more commonly in Africans and Asians, whereas the palpebral form occur more among the Europeans and the Americas. ,,,,,,,,
In Europe and Asia, VKC tends to get worse during winter, , but in Africa patients with VKC are seen all year round. ,, Studies on VKC in Nigeria were mainly in the southern part of the country and showed varying results of presentations. ,,, There are no data on VKC from the Middle Belt area of the country. The purpose of the study is to determine the prevalence and clinical presentation of vernal keratoconjunctivitis in a hospital clinic in Jos, Plateau State, North-Central Nigeria.
| Materials and methods|| |
This is a retrospective hospital-based study of patients with clinical diagnosis of VKC seen from 2000 to 2009 at Adoose Specialist Hospital, Jos, th e capital city of Plateau State in North-Central Nigeria. All available records of consecutive patients with the clinical diagnosis of VKC during the study period were reviewed.
The patients' demographic information and duration of disease, medical history of atopy and other allergic disorders such as asthma, rhinitis/sinusitis, visual acuity (VA) and associated ocular and systemic disorders were extracted from the patients' record.
The VA was determined using the Snellen lettered chart and the tumbling "E" chart for the literate and illiterate patients, respectively. For children below 2 years, their VA was determined by their ability to follow light, faces and to reach out for shiny objects. A pen torch and slit lamp biomicroscope (Marco model 2B, S/N 2999422) were used for assessing the anterior segment while direct and indirect ophthalmoscopes were used for the posterior segment. The definition of VKC was based on the presence both typical VKC-symptoms and key-signs, including bilateral upper giant palpebral conjunctival papillae and/or bulbar conjunctivallimbal papillae infiltration, and corneal keratopathy (i.e., superficial punctate keratitis).
The data collected were analyzed using Statistical Package of the Social Sciences (SPSS) version 17.0 software (SPSS Inc., Chicago, IL, USA). Simple frequencies or cross-tabulations were used to present the data. Chi-squared test was used to compare variables and a P< 0.05 was considered to be statistically significant.
The permission for the study was obtained from the management of Adoose Specialist Hospital Jos.
| Results|| |
Records of 269 patients with clinical diagnosis of vernal keratoconjunctivitis were reviewed. Their ages ranged from 8 months to 44 years. The mean age was 14.6 ± 12.0 years. There were 148 (55%) males and 121 (45%) females. Itching 191 (71%) was the most frequent complaint followed by redness/change in eye color (62.5%). Other complaints included pain (37.5%), watering (33.5%), stickiness of the eyes (20.8%), poor vision (16.7%), foreign body sensation (12.6%) and swollen eyelids (8.2%). [Table 1] shows distribution of symptoms in patients with VKC. Some patients had multiple responses.
Patient presentation was perennial with seasonal exacerbation. The incidence rose steadily from January, peaked in June and declined thereafter. [Figure 1] shows the monthly distribution of patients.
The subjects in age group 0-10 years were most affected by VKC,110 (40.9%). In all, children aged 0-16 years formed 169 (62.8%) of the patients with VKC. After the age of 20 years only a minority of patients presented with VKC. [Table 2] shows the distribution between age and VKC sub-types.
Most of the patients had hyperpigmentation of the conjunctiva. Various sub-types of VKC were presented [Figure 2].
The most prevalent was limbal 125 (46.5%), followed by the mixed type 123 (45.7%). Isolated tarsal 21 (7.8%) sub-type was notcommon. The typical cobble stones papillae were seen in only five (1.9%) patients.
More males presented with VKC in all sub-types, though this did not reach any statistical significance (P = 0.605) [Figure 3].
The most frequently associated ocular condition was refractive error 18 (6.7%) followed by eye lid disorders 9 (3.3%). Keratopathy was present in 6 (2.2%) patients. This included corneal ulcers in 3 and corneal scars in 2 patients and one keratoconus. Episcleritis occurred in 3 patients whereas pterygium and conjunctival neavus were present in 2 patients each. [Figure 4] shows the associated ocular disorders presented. Systemic allergic associations were rare. Most of the patients seen did not present with a related medical or family history of systemic allergic associations. Only 3 patients gave a history of systemic atopy, sinusitis/rhinitis in 2 and only 1 patient was asthmatic.
| Discussion|| |
Vernal keratoconjunctivitis is one of the leading allergic conjunctivitis in the ophthalmological outpatient consultation in most developing part of the world. ,, The mean age of presentation of VKC in the current report was 14.6 years with insignificant male predominance. Children aged 0-16 years formed 62.8% of those with the allergy while after the age of 20 years only a minority of patients (25.7%) presented with VKC. Our findings support previous reports which showed that ocular presentation occurred mainly during the first decade of life. ,,[5 ],,,,,,,,,,,, The sex distribution of VKC is not uniform; whereas in European and Asiatic populations the male to female ratios are as high as 3:1 with sex predilection decreasing with age;  in most African studies there is a less marked male sex predominance. ,,,,, Male predominance is thought to be due to ultraviolet exposure since male children tend to spend more time outdoors (playing with their friends) compared to girls in these countries. In Africa girls also spend a lot of time outside the house running errands, hence the difference in ultraviolet exposure may be less marked. 
Itching was the most frequent complaint. Allergy causes disruption of normal functioning and activities of individuals as a result of the severe allergic symptoms of itching, conjunctivalhyperaemia, chemosis and mucous discharge, which are consequences of leukotriene activities on the conjunctiva. ,,,
The presentation was perennial with seasonal exacerbation. The hospital prevalence rose steadily from January, peaked in June and declined thereafter. This is consistent with onset of the rains from about April and consequent steady increasein the amount of pollens from grass and flowering plants in the air this reaches a peak in June-July-August and declines thereafter during the drier months of December. In most of West Africa from about the end of November a northeasterly trade wind from north of Africa passes over the Sahara Desert parking with it a lot of dust particles. This produces hazy atmospheric conditions, low visibility, low humidity, lower temperatures, and a lot of dust. This is called harmattan season and may contribute allergens in the environment leading to the perennial presentation of patients with VKC. Majokudonmi,  in Ibadan, also observed increased presentation of patients during the wet season. Akinsola et al.  in Lagos University Teaching Hospital however recorded a tri-modal peak pattern (January-February, April-July and September-October).
Although vernal keratoconjunctivitis is a seasonal allergic condition, perennial presentation is not unusual, with seasonal exacerbations during high pollen season in patients living in desert or sub-tropical and tropical climates.  The persistent form of the disease also develops in some patients after about 3 years from onset.  Patients also exhibit conjunctival hyper-reactivity reaction on exposure to dust, wind, sun and non-specific stimuli, hence the occurrence during the harmattan period. 
Most patients seen with VKC had hyperpigmentation of the conjunctiva. Various sub-types of VKC were present. The most prevalent was the limbal (bulbar) form closely followed by mixed sub-type. Isolated tarsal sub-type was the least commonly seen. Typical cobble stones papillae was seen in only five (1.9%) patients. This bulbar predominance agrees with the reports of Sayegh et al. in the Middle East,  Kawuma in Uganda,  Dahan et al. in South Africa  and Sandford-Smith  in Northern Nigeria, but contrasts Ukpomwan  in Benin-Nigeria, Majekudomi  in Lagos-Nigeria and Chenge et al.  in Congo who reported predominant tarsal sub-type. Dahan et al.  in their study among the black children of South Africa observed papillary reaction but without the typical cobble-stone papillae on the tarsal conjunctiva.
The limbal form of the disease has been recognized by various studies. Burnett noted it among the black Americans in 1881.  The predominance of limbal disease among the black population including BlackAmericans suggests a genetic risk factor of VKC. European subjects with VKC develop mainly the palpebral sub-type and Asians develop both ,, Sandford-Smith  in Northern Nigeria noted coexistence of the bulbar and tarsal form of the disease. The predominant bulbar disease was more prevalent among the younger children and the palpebral form in the older patients.
Only a few of our patients had associated ocular condition, the most frequent ones being refractive error followed by eyelid disorders. Due to their high mast cells content with immunoglobulins, other ocular surfaces such as the eyelids, tear film, cornea with the conjunctiva are involved in VKC allergic reaction. Mechanisms of allergic ocular responses has been partially attributed to relaease of cytokines, chemical mediators and adhesion moleculesand complex information exchange among ocular tissues. 
Corneal involvement in the present study was seen in 2.2% of the subjects. Previous reports demonstrated cornea involvement including keratopathy, or corneal shield ulcers and neovascularizationin 3-11% of patients with a superficial. ,
Keratoconus was recorded in only one patient. The use of sensitive instruments such as videokeratography andkeratometryhas been observed to help in early detection of keratoconus.  Refractive error has been found in co-existence with allergic conjunctivitis and is thought to be a risk factor. 
Systemic allergic associations were rare in the current report. History of body atopy was observed in 3 patients, sinusitis/rhinitis in 2 and one bronchial asthma in 1 patient. Family history of atopic diseases such as asthma (26.7%), eczema (9.7%) and rhinitis (20%) has been reported in the European patients with VKC.  In African subjects such history is rare. However, a higher association was recorded by Ajayioba  in Ibadan- Nigeria where careful history and detailed systemic examination found VKC patients had atopy (19.8%) - asthma (6%), allergic rhinitis (5%) and eczema (4.3%). Majekodunmi  in Lagos recorded 10% and Ukponmwa  in Benin 4.5% of systemic associations. Detailed history and examination of patients with VKC may improve detection of associated atopy.
| Conclusion|| |
The study showed that VKC presents largely in early childhood with no significant gender predilection. The disease occurrence was perennial with seasonal accentuation during the wet season. Some ocular associations were noted but there very little systemic associations.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]