AN EPIDEMIOLOGICAL AND CLINICAL STUDY

Background: Pityriasis alba is a common cutaneous disorder usually asymptomatic, hypopigmented macules with or without mild scaling are its presenting lesions. Its etiology and pathogenesis are still poorly understood. Methodology: A descriptive cross-sectional study covered all patients with Pityriasis Alba attended the dermatology department. Results: A total of 86 patients with pityriasis alba, the age range was (2-20) years with a mean age of (8.9) years. Males were 53(61.6%) patients; females were 33(38.4%) patients. The frequency of patients started to decrease with an increase in age. Sunlight was incriminated as an aggravating factor in 32.55% (28 out of 86) patients, soap in 32.55% (28 out of 86) patients, and wind in 10.46% (9 out of 86) patients. Lesions were multiple in 91.8%, face involved in 78 patients (90.7%). History of recurrent illnesswas 21(24.4%), while those with no history of recurrence

Although it is not a clinically serious condition, the aesthetic aspects of the disease are important since it usually attacks the face, presents therapeutic difficulties and has a high incidence in young children (10).
An extensive pityriasis alba is an uncommon clinical variant, the lesions are widespread and distributed symmetrically (11) ,Another variant of classical pityriasis alba showing strong association with dermatophyte infection especially tinea capitis called pigmenting pityriasis alba (12) .
Pityriasis alba is found all over the world. It is quite common, affecting between 1.9 and 5.25% of preadolescent children. The peak of incidence is between the ages of 6 and 12 years (13) . Both sexes are equally susceptible. PA has a high prevalence in infants and children of low socioeconomics conditions in developing countries, being present in 12-90% of children (14) .

Aim of the study:
This study was carried out to have an idea about the epidemiological and clinical aspects of pityriasis alba. This is probably going to reflect this common problem among children.
This study carried out to high light the pityriasis alba through understanding the epidemiological and clinical aspects ofthis common problem.

Patients and Methods:-
A descriptive cross-sectional study conducted at The Dermatology department in Al-Yarmouk Teaching Hospital, during the time extended from November 2017 to June 2018. All patients with a diagnosis of PA attended the dermatology department during that period were included in this study. The study covered 86 patients All patients were questioned regarding their sexes, ages, age of onset of the disease, duration of the disease, season in which the disease appeared, recurrence of the illness, aggravating factors, associated symptoms, personal history of atopy, and family history of same illness or atopy.
A full examination was then done to identify the nature of the lesions, their sites, their numbers, and the color of the skin. Other featuresof atopy were looked for. Wood's light was used to assess the depth and extent of the lesions.

Statistical issue:
Data were entered a computer where they were grouped and analyzed using SPSS software program v23. Data expressed in frequencies and percentages. Chi-square test was used to assess the association between variables.

Ethical issue:
Verbal consents were taken from the participants after the explanation of the research work and assuring the confidentiality of the information obtained.
877 The mean age of onset was 8.3 years. The mean age of onset among male was 8.8 years and among female was 7.9 years.The duration of illness ranged from one week to four years. Table-1 showed that, the frequency of patientsstarted to decrease with an increase in age. The lowest reported cases were in the older age group (16)(17)(18)(19)(20) years, the relationship between age group and gender was not significant (P=0.818).    , and trunk involved in 6 patients (7.0%). The total number of sites of lesions is more than the number of patients becausethere was more than one site involved in some patients.
The number of patients with a history of recurrent illnesswas 21(24.4%), while those with no history of recurrence were 65 patients (75,6%). Positive family history of the same illness was recorded in 36% (31 out of 86) of patients.

Discussion:-
The mean age of patients in this study was 8.9 years, the mean age of onset was 8.3 years, and the mean duration of illness was 4.7 months.This was close toElshafey et al., 2012, who reported that the highest prevalence (12.7%) was in the age group 10-11 years (15) . Al-Fatlawy study found PA more prevalent among children of age group 6-8 years (5) . Alkassaby and El-Masry forward an explanation for the difference in the age distribution of PA that the variation may be due to differences in culture, ethnic group and external environment (16) . Sujatha et al.in their study of 200 cases of pityriasis alba, found the majority (69%) of their cases below 15 years of age (17) . While Sori et al in their study reported lesions of PA in the age range of 5 months-14 years (mean of 6.3 years) (18) .
This study showed a positive history of recurrence in about a quarter of the study patients. In another study,more than one third were recurrent (16) .
This study showed that the atopic patients constitute a 39.5% of patients with PA. PA is a condition of unknown etiology (19) ,but the condition is widely considered as a mild form of atopic dermatitis. Indeed, PA is considered a low-grade eczematous dermatitis and is regarded as a minor feature of atopic dermatitis and a personal or family history of atopy has been found in 85.5% of patients affected by PA (20) ,The results of Lio study found 19 out of 36 cases with PA were atopic. The previous study reported higher rates of atopy (17) but other reported lower rates of atopy (21) , Another researcher claimed that atopic dermatitis is probably more comorbidity of PA than an etiopathogenetic factor (20) .
This study showed that sunlight, soap, and wind were incriminated as an aggravating factor in more than three quarters of the patients. Many studies had named factors like xerosis, wind, soap, and sunlight. as a cause or aggravating condition (12) (22) .But some other studies showed no relation between the disease and factors that may reflect the degree of sun exposure (15) (23) . The differences in results may be due to different methods of assessment of sun exposure or different times of exposure or could be explained by the difference in climates and environmental characteristics of different populations together with other contributing factors in these populations than sun exposure alone (16) .
The majority of patients in the current study presented with multiple lesions. This was similar to Alkassaby and El-Masry study, where the lesions were mostly small in size and multiple in number whereas face was the most common site of affection (16) .
This study found that the face is the only site to be involved in 61.62%of patients, many other sites were involved such as upper and lower extremities trunk and neck. The commonest sites of lesions in Kamal study were the face with 72.7%, followed by arms 13.5%, and neck and chest 4.9% (19) . Face in Alkassaby and El-Masry study was the most common site of affection especially in children (16) .
It was found in this study, that hypopigmentation was present in more than half of the patients, scaling lesions were 880 found in three quarters of patients,and erythema in about one third of the cases. The loss of pigmentation in PA is usually partial and starts at the center and gradually extending toward the periphery (19) . Erythema is often so pale and of short course that it is unnoticeable. The lesions become more notable in summer (20) .
In this study, it was found that 32.5%of patients presented with itching and only 6.9% of patients presented with a burning sensation.Alkassaby and El-Masryreported that pityriasis alba is usually asymptomatic, yet some patients may complain of itching or burning sensation (16) .