Pityriasis alba

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:

1. Raised and red – although the redness is often mild and not noticed by parents
2. Raised and pale
3. Smooth flat pale patches

Lesions are round or oval raised or flat, of 0.5–2 cm in size although may be larger if they occur on the body (up to 4 cm), 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.

The diagnostic differential should consider tinea and vitiligo amongst other causative factors.{{EMedicine|article|762656|Pityriasis Alba}}

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 | vauthors = Vargas-Ocampo F | title = Pityriasis alba: a histologic study | journal = International Journal of Dermatology | volume = 32 | issue = 12 | pages = 870–873 | date = December 1993 | pmid = 8125687 | doi = 10.1111/j.1365-4362.1993.tb01401.x | s2cid = 38371587 }}Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. {{ISBN|0-07-138076-0}}.

The cause of pityriasis alba is not known. Dry skin and atopic dermatitis may co-exist. The patches may become more apparent after sun exposure, when the normal surrounding skin is tanned. The role of ultraviolet radiation, bathing or not bathing, low serum copper and Malassezia yeasts is not clear.

Diagnosis is mainly done by clinical examination. Shining a Wood's light over the skin may reveal further lesions not obviously visible otherwise.

• Pityriasis versicolor and leprosy.{{citation needed|date=March 2020}}

No treatment is required and the patches in time will settle.{{cite journal | vauthors = Lin RL, Janniger CK | title = Pityriasis alba | journal = Cutis | volume = 76 | issue = 1 | pages = 21–24 | date = July 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 | vauthors = Harper J | title = Topical corticosteroids for skin disorders in infants and children | journal = Drugs | volume = 36 Suppl 5 | pages = 34–37 | year = 1988 | pmid = 2978289 | doi = 10.2165/00003495-198800365-00007 | s2cid = 34245207 }}

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 | vauthors = 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 = The British Journal of Dermatology | volume = 155 | issue = 1 | pages = 152–155 | date = July 2006 | pmid = 16792767 | doi = 10.1111/j.1365-2133.2006.07181.x | s2cid = 11694329 }}

In exceptionally severe cases PUVA therapy may be considered.{{cite journal | vauthors = 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 | volume = 19 | issue = 3 | pages = 370–372 | date = May 2005 | pmid = 15857470 | doi = 10.1111/j.1468-3083.2004.01170.x | s2cid = 7454859 }}

The patches of pityriasis alba may last from 1 month to about one year, but commonly on the face last a year. However it is possible that the white patches may last for more than 1 year on the face.

It occurs in mainly children and adolescents of all races, particularly people with dark skin. The worldwide prevalence is 5% in children, with boys and girls affected equally.{{Cite web|url=https://dermnetnz.org/topics/pityriasis-alba/|title=Pityriasis alba {{!}} DermNet NZ|website=dermnetnz.org|language=en|access-date=12 March 2020}} adults can also have this disease.{{cite journal | vauthors = 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 | volume = 16 | issue = 5 | pages = 463–468 | date = September 2002 | pmid = 12428838 | doi = 10.1046/j.1468-3083.2002.00494.x | s2cid = 41808052 }}

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 | vauthors = 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 = 470–473 | year = 2003 | pmid = 14651562 | doi = 10.1111/j.1525-1470.2003.20602.x | s2cid = 20609987 }}

to 31%.{{cite journal | vauthors = 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 = 144–146 | date = June 2005 | doi = 10.47276/lr.76.2.144 | pmid = 16038247 | doi-access = free }}

Other studies have shown prevalence rates in Brazil of 9.9%,{{cite journal | vauthors = Bechelli LM, Haddad N, Pimenta WP, Pagnano PM, Melchior E, Fregnan RC, Zanin LC, Arenas A | display-authors = 6 | 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 | doi = 10.1159/000250144 }}

Egypt 13.49%,{{cite journal | vauthors = Abdel-Hafez K, Abdel-Aty MA, Hofny ER | title = Prevalence of skin diseases in rural areas of Assiut Governorate, Upper Egypt | journal = International Journal of Dermatology | volume = 42 | issue = 11 | pages = 887–892 | date = November 2003 | pmid = 14636205 | doi = 10.1046/j.1365-4362.2003.01936.x | s2cid = 12046365 }}

Romania 5.1%,{{cite journal | vauthors = Popescu R, Popescu CM, Williams HC, Forsea D | title = The prevalence of skin conditions in Romanian school children | journal = The British Journal of Dermatology | volume = 140 | issue = 5 | pages = 891–896 | date = May 1999 | pmid = 10354028 | doi = 10.1046/j.1365-2133.1999.02821.x | s2cid = 40160452 | doi-access = free }}

Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,{{cite journal | vauthors = 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 = 307–311 | year = 2002 | pmid = 12220273 | doi = 10.1046/j.1525-1470.2002.00087.x | s2cid = 22690794 }}

and just 1% in school children in Hong Kong.{{cite journal | vauthors = 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 = 440–446 | year = 2000 | pmid = 11123774 | doi = 10.1046/j.1525-1470.2000.01841.x | s2cid = 24117322 }} In 1963, one school health clinic reported features of pityriasis alba in two fifths of their children.

It was first described in 1923. Having been known under a variety of names, the term 'Pityriasis alba', coined in 1956, has stayed.{{Cite book | vauthors = Lacour JP | chapter = Inflammatory Hypomelanoses. | veditors = Nordlund JJ, Boissy RE, Hearing VJ, King RA, Oetting WS, Ortonne JP |chapter-url=https://books.google.com/books?id=4sn46U1uexoC&pg=PA699|title=The Pigmentary System: Physiology and Pathophysiology|date=2008|publisher=John Wiley & Sons|isbn=978-1-4051-5733-9|language=en}}{{cite journal | vauthors = O'Farrell NM | title = Pityriasis alba | journal = A.M.A. Archives of Dermatology | volume = 73 | issue = 4 | pages = 376–377 | date = April 1956 | pmid = 13301055 | doi = 10.1001/archderm.1956.01550040070010 | s2cid = 40381881 }}

• Leprosy
• List of cutaneous conditions
• Vitiligo which, by comparison, causes total loss of skin colour or on the face and tends to occur around the mouth and eyes.

{{Reflist}}

{{Medical resources

| DiseasesDB = 31121

| ICD10 = {{ICD10|L|30|5|l|20}} (ILDS L30.590)

| ICD9 = {{ICD9|696.5}}

| ICDO =

| OMIM =

| MedlinePlus = 001463

| eMedicineSubj = ped

| eMedicineTopic = 1813

| eMedicine_mult = {{eMedicine2|derm|333}} {{eMedicine2|emerg|425}}

| MeshID =

}}

{{Diseases of the skin and appendages by morphology}}

{{Diseases of the skin and subcutaneous tissue}}

{{Pigmentation disorders}}

Category:Disturbances of human pigmentation