Atopic dermatitis is an allergic hypersensitivity reaction, affecting skin inflammation. It is estimated that about 20% of children experience symptoms of this disease. Atopic dermatitis presents itself in the form of intense itching, blisters with oozing or crusting, skin rashes, ichthyosis, thick leathery skin (lichenification), and small, rough bumps (keratosis pilaris), especially on the face, upper arm, and thighs. Other parts affected include the under eye portion, where an extra fold of skin (Dennie-Morgan fold) may develop, the palm, which may show extra skin creases, and eyelids, which become hyperpigmented. About 75% of children affected with atopic eczema go ahead to develop hay fever or asthma. In some patients, the condition may also be associated with allergic rhinitis, food allergy, urticaria (hive formation), and/or increased IgE production. Various theories exist on the pathophysiology of atopic dermatitis. These include an immune defect involving an abnormality of TH2 cells, a defective barrier function in the stratum corneum, and a defective ceramide production leading to xerosis.
The major medication prescribed for atopic dermatitis is topical steroids. Other forms of management recommended are application of moisturizers or other topical creams to reduce the drying of the skin, using a soap substitute such as an aqueous cream, avoiding contact with known allergens, and controlling stress, nervousness, anxiety, and depression.
Atopic dermatitis has a definite genetic component. This is exemplified by an increased risk for children with a family history of the condition to develop it themselves, and an increased incidence of the disease in the other pair of an affected monozygotic twin. It is now considered that the disease actually presents itself as a result of a combination of genetic and environmental factors. Complete genome-wide screening in affected families has identified at least 19 genes associated with the condition, implying a multifactorial background. Some of these identified loci have been found to overlap with loci implicated in psoriasis, indicating a common mechanism for these two dermatological conditions. Other candidate genes identified include filaggrin, serine protease inhibitors, toll receptors, chymases, and various cytokines.
Najim et al., (2005) carried out a study to determine acetylator status in 35 Iraqis with allergic contact dermatitis (ACD) patients and 67 healthy controls. Among the ACD patients, there were 13 males and 22 females, aged between 17 and 43 years. Of the 35 patients, 21 were slow acetylators with a frequency of 60%, while the frequency of rapid acetylators was 40.0%. Forty-eight of 67 healthy controls were slow acetylators (72%) and the frequency of rapid acetylators was 28.4%. There was a significant difference between the rapid acetylator status in ACD patient and healthy controls. There was no significant association between the acetylator statuses, personal history of allergy, sites of dermatitis or patch-test positivity in ACD patients.
Nanda et al. (1999) studied the spectrum and pattern of skin diseases of children in Kuwait in 10,000 consecutive new patients; 96% were children of Arab descent. A female preponderance (52%) was observed, and infants constituted the largest group within the patient population (28.7%). A total of 162 dermatoses were recorded. Atopic dermatitis was the most prevalent dermatosis (31.3%), followed by viral warts (13.1%), alopecia areata (6.7%), pityriasis alba (5.25%), psoriasis (4%), and diaper dermatitis (4%). Atopic dermatitis was the most frequently seen dermatosis in children of all age groups.
As part of the ISSAC (international study of asthma and allergies in childhood) Phase I, Al-Riyami et al. (2003) conducted a nationwide study to determine the prevalence of atopic eczema in Oman. Data was collected from all pupils (divided into 6-7 age group and 13-14 age group) of a randomly selected class of a randomly selected school by filling up the ISSAC questionnaire. Approximately 3000 children in each of the groups were interviewed, 99% of which were Omanis. About 95.4% of the 6-7 years age group (3893 children), and 89.5% (3174 children) of the 13-14 years age group completed the questionnaire. The cumulative prevalence rate of atopic eczema was higher in the 13-14 years old group (14.4%) when compared to the younger age group (7.4%). Similarly, the prevalence rate of chronic rash also showed a statistically significant difference between the two groups (10.2% and 12.6%). However, the 12-month prevalence of rash with atopic distribution (5.8% and 5.2%) was almost similar between the two groups. The prevalence rate of parent-reported diagnosis and symptoms of atopic eczema was found to be higher than those in Iran. In view of the high prevalence rates of reported symptoms and diagnosis of this condition which was associated with high morbidity as reflected by the nights disturbed, Al-Riyami et al. (2003) concluded that more studies needed to be done to determine the possible causes of under-diagnosis and under-management of this condition to improve its control.
El-Tonsy et al. (1998) studied 87 patients (33 Qatari and 54 other nationalities; 73 males and 14 females; 76 adults and 11 children; aged 2-56 years) with alopecia areata (AA). They found five patients (5.8%) to have atopic dermatitis, and 19 patients (21.8%) were found to have a family history for atopic dermatitis.
Janahi et al. (2006) undertook the first ever study to determine the prevalence of allergic diseases among schoolchildren in Qatar. A total of 3,500 Qatari schoolchildren, aged between 6 and 14 years, were selected from both rural and urban areas, based on a stratified, random sampling technique. Parents of all selected subjects were asked to fill questionnaires based on ISAAC intending to diagnose asthma or allergic rhinitis in their child. The response rate was 93.8%, with 3,283 of the subjects returning properly filled questionnaires. Males constituted 52.3% of the study group. A high prevalence of eczema (738 subjects; 22.5%) was diagnosed in the study population. This prevalence was higher than earlier reports from Saudi Arabia and the United Arab Emirates. Interestingly, the prevalence was found to decrease with increasing age. Males were found to be more susceptible to eczema, especially among the youngest age group (6-8 years). Eczema was found to be closely associated with other allergic conditions, with 56.9% of the affected subjects also found to have either asthma and/or allergic rhinitis.
Bin-Obaid (1997) reported 79 (49 males and 30 females) patients with atopic dermatitis diagnosed clinically and evaluated by measuring total serum IgE antibody levels and specific IgE antibodies (RAST) to house dust mixture. Patients who had another disease which may cause high serum IgE levels were excluded. The patients' ages ranged between 2-81 years with a mean age of 30 years. Bin-Obaid (1997) found that serum IgE levels correlate with severity of the disease, and 41 out of the 79 patients (52%) had statistically significant RAST reactivity to house dust mixture. He also found that serum IgE levels were higher in patients showing specific IgE antibodies against house dust mixture in their serum.
Lestringant et al. (1996) described three patients with an association of lichen nitidus and atopic dermatitis (AD).
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