الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 75 |  |  |
| | | from | 75 | | |
Abstract
Pityriasis alba PA is a common skin disorder characterized by white or pink irregular scaling plaques with well defined borders, varying from 0.5 to 6 cm in diameter. It affects the face in over 50% of cases, and most patients are children between 6 and 16 years of age. Males are thought to be affected more frequently than females (male/female ratio 1.73: 1) as well as individuals with darker skin color.
Other contributory factors, besides infective agents, have been related to the genesis of PA. Among them, environmental influences, such as temperature variations, relative air humidity, altitude and excessive sun light exposure, have been blamed. Ultraviolet radiation may also be implicated, considering that excessive skin irritation induces inflammatory reactions, and that the direct action of sunlight over melanocytes modifies their function, leading to a decrease in the intensity of color in PA lesions.
Among dermatological conditions, atopic dermatitis (AD) can also lead to or worsen cutaneous dryness.
In spite of the benign course of the disease, PA is a frequent reason for skin consultation, especially because of its chronic course, tendency to relapse, bad cosmetic appearance and frustrating treatment. Therefore, the objective of the present study was to try to correlate the suspected
triggering factors for PA with epidemiological data, comparing clinical cases with a matched control group.
This descriptive comparative study was carried out in dermatology outpatient clinic, Suez Canal University Hospital in Ismailia.
Our work aimed at estimation of serum level of IL-4 and Ig-E in pityriasis alba patients.
This work was conducted on 30 patients and 30 control groups, their age ranged from 3 to 16 years and they were subjected to history taking and physical examination with special emphasis on personal history and family history of allergic diseases. Blood samples were taken for assessment of serum levels of IL-4 and Ig-E.
Most patients were males (63%) and (27%) of patients have positive family history of AD, and 23% of patient had a positive family history of P. alba. Parasitic infestations were detected 20% of patients.
Serum level of IL-4 was (62.53±15.72 pg. /ml) in PA patients group, on the other hand it was (33.13± 21.92 pg. /ml) in control group.
IgE level was (228.26 ± 276.6 I.U/ml) and (76.76 ± 125.13 IU/ ml) for the P.A patients and control group respected.
There were statistically significant differences between P.A patients and control group regarding serum IL-4 and IgE level.
However no relation was found between IL-4 and IgE level in p.alba patients. IL-4 level was significantly higher in p. alba patients who had family history of A.D. compared to those without family history of A.D., but there was no statistically significant difference of IgE level in patients with and without family history of A.D.
Also, IL-4 level was significantly higher in p. alba patients who had family history of parasitic infestation compared to those without parasitic infestation but there was no statistically significant difference of IgE level in patients with and without parasitic infestations.
Results of the present study revealed that in conclusion:
Imbalance of IL-4 level may play a critical role in pathogenesis of P.A.
Changed balance of IL-4 level may be related to the genetic background of patients, which need more study.
Perhaps the environmental factors play important role in affecting genetic background in relation to IL-4.