Pityriasis alba

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 31121
ICD10 = ICD10|L|30|5|l|20
ICD9 = ICD9|696.5
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = ped
eMedicineTopic = 1813
eMedicine_mult = eMedicine2|derm|333 eMedicine2|emerg|425
MeshID =

Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturiser creams.

The condition is so named for the fine scaly appearance initially present (pityriasis) and the pallor of the patches that develop (while "alba" is Latin for white, the patches in this condition are not totally depigmented)cite journal |author=Pinto FJ, Bolognia JL |title=Disorders of hypopigmentation in children |journal=Pediatr. Clin. North Am. |volume=38 |issue=4 |pages=991–1017 |year=1991 |pmid=1870914] .

Aetiology

There is no specific known cause for this condition, but any dermatitis may heal leaving pale skin, as may excessive use of corticosteroid creams used to treat episodes of eczema. The hypopigmentation is due to both reduced activity of melanocytes with fewer and smaller melanosomes. [cite journal |author=Vargas-Ocampo F |title=Pityriasis alba: a histologic study |journal=Int. J. Dermatol. |volume=32 |issue=12 |pages=870–3 |year=1993 |pmid=8125687 |doi=10.1111/j.1365-4362.1993.tb01401.x]

The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females. [cite journal |author=Blessmann Weber M, Sponchiado de Avila LG, Albaneze R, Magalhães de Oliveira OL, Sudhaus BD, Cestari TF |title=Pityriasis alba: a study of pathogenic factors |journal=Journal of the European Academy of Dermatology and Venereology : JEADV |volume=16 |issue=5 |pages=463–8 |year=2002 |pmid=12428838 |doi=10.1046/j.1468-3083.2002.00494.x] It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions. [cite journal |author=Laude TA |title=Approach to dermatologic disorders in black children |journal=Seminars in dermatology |volume=14 |issue=1 |pages=15–20 |year=1995 |pmid=7742234]

Up to a third of US school children may at some stage have this condition. Single-point prevalence studies from India have shown variable rates from 8.4%, [cite journal |author=Dogra S, Kumar B |title=Epidemiology of skin diseases in school children: a study from northern India |journal=Pediatric dermatology |volume=20 |issue=6 |pages=470–3 |year=2003 |pmid=14651562 |doi=10.1111/j.1525-1470.2003.20602.x] to 31%. [cite journal |author=Faye O, N'Diaye HT, Keita S, Traoré AK, Hay RJ, Mahé A |title=High prevalence of non-leprotic hypochromic patches among children in a rural area of Mali, West Africa |journal=Leprosy review |volume=76 |issue=2 |pages=144–6 |year=2005 |pmid=16038247] Other studies have shown prevalence rates in Brazil of 9.9%, [cite journal |author=Bechelli LM, Haddad N, Pimenta WP, Pagnano PM, Melchior E, Fregnan RC, Zanin LC, Arenas A |title=Epidemiological survey of skin diseases in schoolchildren living in the Purus Valley (Acre State, Amazonia, Brazil) |journal=Dermatologica |volume=163 |issue=1 |pages=78–93 |year=1981 |pmid=7274519] Egypt 13.49%, [cite journal |author=Abdel-Hafez K, Abdel-Aty MA, Hofny ER |title=Prevalence of skin diseases in rural areas of Assiut Governorate, Upper Egypt |journal=Int. J. Dermatol. |volume=42 |issue=11 |pages=887–92 |year=2003 |pmid=14636205 |doi=10.1046/j.1365-4362.2003.01936.x] Romania 5.1%, [cite journal |author=Popescu R, Popescu CM, Williams HC, Forsea D |title=The prevalence of skin conditions in Romanian school children |journal=Br. J. Dermatol. |volume=140 |issue=5 |pages=891–6 |year=1999 |pmid=10354028 |doi=10.1046/j.1365-2133.1999.02821.x] Turkey 12% where higher rates were seen in those with poor socioeconomic conditions, [cite journal |author=Inanir I, Sahin MT, Gündüz K, Dinç G, Türel A, Oztürkcan S |title=Prevalence of skin conditions in primary school children in Turkey: differences based on socioeconomic factors |journal=Pediatric dermatology |volume=19 |issue=4 |pages=307–11 |year=2002 |pmid=12220273 |doi=10.1046/j.1525-1470.2002.00087.x] and just 1% in school children in Hong Kong. [cite journal |author=Fung WK, Lo KK |title=Prevalence of skin disease among school children and adolescents in a Student Health Service Center in Hong Kong |journal=Pediatric dermatology |volume=17 |issue=6 |pages=440–6 |year=2000 |pmid=11123774 |doi=10.1046/j.1525-1470.2000.01841.x]

ymptoms and signs

The dry scaling appearance is most noticeable during the winter as a result of dry air inside people's homes. During the summer, tanning of the surrounding normal skin makes the pale patches of pityriasis alba more prominent.

Individual lesions develop through 3 stages and sometimes are itchy:
# Raised and red - although the redness is often mild and not noticed by parents
# Raised and pale
# Smooth flat pale patches

Lesions are round or oval, of 0.5-2 cm in size although may be larger if they occur on the body (up to 4cm), and usually number from 4 or 5 to over 20. The patches are dry with very fine scales. They most commonly occur on the face (cheeks), but in 20% appear also on the upper arms, neck, or shoulders.

Treatment

No treatment is required and the patches in time will settle. [cite journal |author=Lin RL, Janniger CK |title=Pityriasis alba |journal=Cutis; cutaneous medicine for the practitioner |volume=76 |issue=1 |pages=21–4 |year=2005 |pmid=16144284] The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used. [cite journal |author=Harper J |title=Topical corticosteroids for skin disorders in infants and children |journal=Drugs |volume=36 Suppl 5 |issue= |pages=34–7 |year=1988 |pmid=2978289]

As the patches of pityriasis alba do not darken normally in sunlight, effective sun protection helps minimise the discrepancy in colouration against the surrounding normal skin. Cosmetic camouflage may be required.

Tacrolimus has been reported as speeding resolution. [cite journal |author=Rigopoulos D, Gregoriou S, Charissi C, Kontochristopoulos G, Kalogeromitros D, Georgala S |title=Tacrolimus ointment 0.1% in pityriasis alba: an open-label, randomized, placebo-controlled study |journal=Br. J. Dermatol. |volume=155 |issue=1 |pages=152–5 |year=2006 |pmid=16792767 |doi=10.1111/j.1365-2133.2006.07181.x]

In exceptionally severe cases PUVA therapy may be considered. [cite journal |author=Di Lernia V, Ricci C |title=Progressive and extensive hypomelanosis and extensive pityriasis alba: same disease, different names? |journal=Journal of the European Academy of Dermatology and Venereology : JEADV |volume=19 |issue=3 |pages=370–2 |year=2005 |pmid=15857470 |doi=10.1111/j.1468-3083.2004.01170.x]

Prognosis

The patches of pityriasis alba may last from 1 month to 10 years, but commonly on the face last a year or more.

ee also

* Vitiligo which, by comparison, causes total loss of skin colour and on the face tends to occur around the mouth and eyes.cite journal |author=Pinto FJ, Bolognia JL |title=Disorders of hypopigmentation in children |journal=Pediatr. Clin. North Am. |volume=38 |issue=4 |pages=991–1017 |year=1991 |pmid=1870914]

References