Pityriasis alba

Pityriasis alba is a skin condition, a type of dermatitis,[1] commonly seen in children and young adults as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer creams.[2]

Pityriasis alba
SpecialtyDermatology 

The condition is so named for the fine scaly appearance initially present (pityriasis), and alba (Latin for white) refers to the pallor of the patches that develop. The patches are not totally depigmented.[3]

Signs and symptoms

The dry scaling appearance is most noticeable during the winter as a result of dry air inside people's homes.[1] During the summer, tanning of the surrounding normal skin makes the pale patches of pityriasis alba more prominent.[1]

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[1]

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.[1][2]

The diagnostic differential should consider tinea and vitiligo amongst other causative factors.[4]

Cause

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.[5][6]

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.[1] The role of ultraviolet radiation, bathing or not bathing, low serum copper and Malassezia yeasts is not clear.[1]

Diagnosis

Diagnosis is mainly done by clinical examination. Shining a Wood's light over the skin may reveal further lesions not obviously visible otherwise.[2]

Differential diagnosis
  • Pytriasis versicolor and leprosy.

Treatment

No treatment is required and the patches in time will settle.[7] The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.[8]

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.[9]

In exceptionally severe cases PUVA therapy may be considered.[10]

Prognosis

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.

Epidemiology

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.[1] adults can also suffer from this disease.[11]

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%[12] to 31%.[13] Other studies have shown prevalence rates in Brazil of 9.9%,[14] Egypt 13.49%,[15] Romania 5.1%,[16] Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,[17] and just 1% in school children in Hong Kong.[18] In 1963, one school health clinic reported features of pityriasis alba in two fifths of their children.[2]

History

It was first described in 1923. Having been known under a variety of names, the term 'Pityriasis alba', coined in 1956, has stayed.[2][19]

gollark: Done.
gollark: I could do that, but I'm busy.
gollark: ++remind 1h inolementbtbr
gollark: Good idea, I didn't think of that.
gollark: From Discord.

See also
  • 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.[3]

References
  1. "Pityriasis alba | DermNet NZ". dermnetnz.org. Retrieved 12 March 2020.
  2. Nordlund, James J.; Boissy, Raymond E.; Hearing, Vincent J.; King, Richard A.; Oetting, William S.; Ortonne, Jean-Paul (2008). The Pigmentary System: Physiology and Pathophysiology. John Wiley & Sons. ISBN 978-1-4051-5733-9.
  3. Pinto FJ, Bolognia JL (1991). "Disorders of hypopigmentation in children". Pediatric Clinics of North America. 38 (4): 991–1017. doi:10.1016/S0031-3955(16)38164-0. PMID 1870914.
  4. Pityriasis Alba at eMedicine
  5. Vargas-Ocampo F (1993). "Pityriasis alba: a histologic study". Int. J. Dermatol. 32 (12): 870–873. doi:10.1111/j.1365-4362.1993.tb01401.x. PMID 8125687.
  6. Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN 0-07-138076-0.
  7. Lin RL, Janniger CK (2005). "Pityriasis alba". Cutis; Cutaneous Medicine for the Practitioner. 76 (1): 21–4. PMID 16144284.
  8. Harper J (1988). "Topical corticosteroids for skin disorders in infants and children". Drugs. 36 Suppl 5: 34–7. doi:10.2165/00003495-198800365-00007. PMID 2978289.
  9. Rigopoulos D, Gregoriou S, Charissi C, Kontochristopoulos G, Kalogeromitros D, Georgala S (2006). "Tacrolimus ointment 0.1% in pityriasis alba: an open-label, randomized, placebo-controlled study". Br. J. Dermatol. 155 (1): 152–155. doi:10.1111/j.1365-2133.2006.07181.x. PMID 16792767.
  10. Di Lernia V, Ricci C (2005). "Progressive and extensive hypomelanosis and extensive pityriasis alba: same disease, different names?". Journal of the European Academy of Dermatology and Venereology : JEADV. 19 (3): 370–372. doi:10.1111/j.1468-3083.2004.01170.x. PMID 15857470.
  11. Blessmann Weber M, Sponchiado de Avila LG, Albaneze R, Magalhães de Oliveira OL, Sudhaus BD, Cestari TF (2002). "Pityriasis alba: a study of pathogenic factors". Journal of the European Academy of Dermatology and Venereology : JEADV. 16 (5): 463–468. doi:10.1046/j.1468-3083.2002.00494.x. PMID 12428838.
  12. Dogra S, Kumar B (2003). "Epidemiology of skin diseases in school children: a study from northern India". Pediatric Dermatology. 20 (6): 470–473. doi:10.1111/j.1525-1470.2003.20602.x. PMID 14651562.
  13. Faye O, N'Diaye HT, Keita S, Traoré AK, Hay RJ, Mahé A (2005). "High prevalence of non-leprotic hypochromic patches among children in a rural area of Mali, West Africa". Leprosy Review. 76 (2): 144–6. PMID 16038247.
  14. Bechelli LM, Haddad N, Pimenta WP, Pagnano PM, Melchior E, Fregnan RC, Zanin LC, Arenas A (1981). "Epidemiological survey of skin diseases in schoolchildren living in the Purus Valley (Acre State, Amazonia, Brazil)". Dermatologica. 163 (1): 78–93. doi:10.1159/000250144. PMID 7274519.
  15. Abdel-Hafez K, Abdel-Aty MA, Hofny ER (2003). "Prevalence of skin diseases in rural areas of Assiut Governorate, Upper Egypt". Int. J. Dermatol. 42 (11): 887–892. doi:10.1046/j.1365-4362.2003.01936.x. PMID 14636205.
  16. Popescu R, Popescu CM, Williams HC, Forsea D (1999). "The prevalence of skin conditions in Romanian school children". Br. J. Dermatol. 140 (5): 891–896. doi:10.1046/j.1365-2133.1999.02821.x. PMID 10354028.
  17. Inanir I, Sahin MT, Gündüz K, Dinç G, Türel A, Oztürkcan S (2002). "Prevalence of skin conditions in primary school children in Turkey: differences based on socioeconomic factors". Pediatric Dermatology. 19 (4): 307–311. doi:10.1046/j.1525-1470.2002.00087.x. PMID 12220273.
  18. Fung WK, Lo KK (2000). "Prevalence of skin disease among school children and adolescents in a Student Health Service Center in Hong Kong". Pediatric Dermatology. 17 (6): 440–446. doi:10.1046/j.1525-1470.2000.01841.x. PMID 11123774.
  19. O'farrell, Norman M. (1 April 1956). "Pityriasis Alba". A.M.A. Archives of Dermatology. 73 (4): 376–377. doi:10.1001/archderm.1956.01550040070010. ISSN 0096-5359.
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