Pityriasis alba "النخالة البيضاء"

*presentation:-
-حالة شائعة جدا بيكون فيها بقعة بيضاء غالبا في وجه الاطفال

●50%in face
●30%in neck ,upper limb
*causes:-
Un known but may be due to
1-vitamin deficiency.. نقص فيتامينات
2-anemia ..أنيميا
3-parasitic infection..ديدان
4-prolonged use of potent topical steroid
5-sun exposure...مش بتسبب البقعة لكن بتزود اسمرار الجلد حولها فتظهر أكتر
*Treatment :-
-بعد علاج كل الأسباب المحتملة الحالة غالبا بتروح لوحدها في خلال سهور بس وصف كريم كورتيزون ذو تأثير ضعيف بيساعد على اختفاء البقعة اسرع
1-treatment of all possible causes
●vitamin supplement
Ex:- totavit syrup
ملعقة واحدة يوميا لمدة شهر أو شهرين
●CBC &iron supplement for anemia
Ex:-haemojet syrup
ملعقة واحدة يوميا امدة شهرين
●stool analysis.......تحليل براز مع علاج للديدان ان وجدت
●stop using potent topical steroids
●avoid sun exposure.....ممنوع التعرض للشمس

2-mild potency topical steroid


What is pityriasis alba?

-Pityriasis alba is a low-grade type of eczema/dermatitis that primarily affects children.

-The name refers to its appearance: pityriasis refers to its characteristic fine scale, and alba to its pale colour (hypopigmentation).

Who gets pityriasis alba?....شائع في الأطفال والمراهقين وخاصة ذوات البشرة الداكنة

-Pityriasis alba is common worldwide with a prevalence in children of around 5%.

-It mainly affects children and adolescents aged 3 to 16 years, but may also arise in older and younger people
-It affects boys and girls equally.
-It is more prominent, and may also be more prevalent, in dark skin compared to white skin.
What causes pityriasis alba?

The cause of pityriasis alba is unknown......سببه غير معروف

-It often coexists with dry skin and atopic dermatitis.....ياتي في اغلب الأحيان اثناء التهاب الجلد وجفافه
-It often presents following sun exposure, perhaps because tanning of surrounding skin makes affected areas more prominent.
-Researchers have not reached any conclusions about the relationship of pityriasis alba to the following:

●Ultraviolet radiation
●Excessive or inadequate bathing
●Low levels of serum copper
●Malassezia yeasts
(which produce a metabolite, pityriacitrin, that inhibits tyrosinase thus causing hypopigmentation)

What are the clinical features of pityriasis alba?

-Classic pityriasis alba usually presents with 1 to 20 patches or thin plaques.

-Most lesions occur on the face, especially on cheeks and chin.
-They may also arise on neck, shoulders and upper arm and are uncommon on other sites of the body.
-Size varies from 0.5 to 5 cm in diameter.
-They are round, oval or irregular in shape.
-Pityriasis alba may have well-demarcated or poorly defined edges.
-Itch is minimal or absent.
-Hypopigmentation is more noticeable in summer, especially in dark-skinned children.
-Dryness and scaling is more noticeable in winter, when environmental humidity tends to be lower.
-Typically, each area of pityriasis alba goes through several stages.

-Slightly scaly pink plaque with just palpable papular surface
Hypopigmented plaque with fine surface scale
-Then post-inflammatory hypopigmented macule without scale
Resolution


Complications of pityriasis alba

-None are known.

How is pityriasis alba diagnosed?

-Pityriasis alba can be confused with several other disorders that cause hypopigmentation.

To exclude these, investigations may include:

●Wood lamp examination:
hypopigmentation does not enhance, and there is no fluorescence in pityriasis alba
●Scrapings for mycology: microscopy and fungal culture are negative in pityriasis alba
●Skin biopsy: biopsy is rarely required, but may reveal mildly spongiotic dermatitis and reduction in melanin
What is the treatment for pityriasis alba?

-No treatment is necessary for asymptomatic pityriasis alba.

-A moisturising cream may improve the dry appearance
-A mild topical steroid (hydrocortisone) cream may reduce redness and itch
-Calcineurin inhibitors, pimecrolimus cream and tacrolimus ointment, may be as effective as hydrocortisone and have been reported to speed recovery of skin colour.

How can pityriasis alba be prevented?

-The development or prominence of pityriasis alba can be reduced by avoiding exposure to sunlight.

**What is the outlook for pityriasis alba?

-Pityriasis clears up after a few months, or in some cases persists for up to two or three years. The colour gradually returns completely to normal.

تعليقات