| 词条 | Pityriasis alba |
| 释义 |
| name = Pityriasis alba | synonyms = | image = | caption = | pronounce = | field = | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }} Pityriasis alba is a common skin condition mostly occurring in children and young adults usually seen as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer 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).[1] Signs and symptomsThe 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:
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.[2] CauseAny 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.[3][4] The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females. However adults can also suffer from this disease.[5] It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions.[6] 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%,[7] to 31%.[8] Other studies have shown prevalence rates in Brazil of 9.9%,[9] Egypt 13.49%,[10] Romania 5.1%,[11] Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,[12] and just 1% in school children in Hong Kong.[13] DiagnosisDiagnosis is mainly done by clinical examination. D/d to rule out is Pytriasis versicolor and leprosy {{Empty section|date=April 2017}}TreatmentNo treatment is required and the patches in time will settle.[14] The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.[15] 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.[16]In exceptionally severe cases PUVA therapy may be considered.[17] PrognosisThe 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. See also
References1. ^1 {{cite journal |vauthors=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}} 2. ^{{EMedicine|article|762656|Pityriasis Alba}} 3. ^{{cite journal |author=Vargas-Ocampo F |title=Pityriasis alba: a histologic study |journal=Int. J. Dermatol. |volume=32 |issue=12 |pages=870–873 |year=1993 |pmid=8125687 |doi=10.1111/j.1365-4362.1993.tb01401.x}} 4. ^Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. {{ISBN|0-07-138076-0}}. 5. ^{{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 : JEADV |volume=16 |issue=5 |pages=463–468 |year=2002 |pmid=12428838 |doi=10.1046/j.1468-3083.2002.00494.x}} 6. ^{{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 |doi=10.1016/S1085-5629(05)80034-3}} 7. ^{{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}} 8. ^{{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=144–6 |year=2005 |pmid=16038247}} 9. ^{{cite journal |vauthors=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 |doi=10.1159/000250144 }} 10. ^{{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=Int. J. Dermatol. |volume=42 |issue=11 |pages=887–892 |year=2003 |pmid=14636205 |doi=10.1046/j.1365-4362.2003.01936.x}} 11. ^{{cite journal |vauthors=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=891–896 |year=1999 |pmid=10354028 |doi=10.1046/j.1365-2133.1999.02821.x}} 12. ^{{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}} 13. ^{{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}} 14. ^{{cite journal |vauthors=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}} 15. ^{{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 |doi=10.2165/00003495-198800365-00007}} 16. ^{{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=Br. J. Dermatol. |volume=155 |issue=1 |pages=152–155 |year=2006 |pmid=16792767 |doi=10.1111/j.1365-2133.2006.07181.x}} 17. ^{{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 : JEADV |volume=19 |issue=3 |pages=370–372 |year=2005 |pmid=15857470 |doi=10.1111/j.1468-3083.2004.01170.x}} External links{{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}} 1 : Disturbances of human pigmentation |
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