Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine scaled, pale patches on their faces. 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 palor of the patches that develop (whilst "alba" is Latin for white, the patches in this condition are not totally depigmented).
There is no specific known cause for this condition, but any dermatitis inflammation of the skin 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.
The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females.
It possibly occurs more frequently in those of light-skin, but is more apparent in those of darker complexion.
Up to a third of US school children may at some stage get this condition. Single point prevalence studies from India have shown variable rates from 8.4%,
Other studies have shown prevalence rates in Brazil of 9.9%,
Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,
and just 1% in school children in Hong Kong.
Symptoms 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.
No treatment is required and the patches in time will settle.
The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.
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.
In exceptionally severe cases PUVA therapy may be considered.
The patches of PA may last from 1 month to 10 years, but commonly on the face last a year or more.
Vitiligo which, by comparison, causes total loss of skin colour and on the face tends to occur around the mouth.
^ ab Pinto FJ, Bolognia JL (1991). "Disorders of hypopigmentation in children". Pediatr. Clin. North Am.38 (4): 991-1017. PMID 1870914.
^ Vargas-Ocampo F (1993). "Pityriasis alba: a histologic study". Int. J. Dermatol.32 (12): 870-3. PMID 8125687.
^ 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 : JEADV16 (5): 463-8. PMID 12428838.
^ Laude TA (1995). "Approach to dermatologic disorders in black children". Seminars in dermatology14 (1): 15-20. PMID 7742234.
^ Dogra S, Kumar B (2003). "Epidemiology of skin diseases in school children: a study from northern India". Pediatric dermatology20 (6): 470-3. PMID 14651562.
^ 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 review76 (2): 144-6. PMID 16038247.
^ 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)". Dermatologica163 (1): 78-93. PMID 7274519.
^ 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): 887-92. PMID 14636205.
^ Popescu R, Popescu CM, Williams HC, Forsea D (1999). "The prevalence of skin conditions in Romanian school children". Br. J. Dermatol.140 (5): 891-6. PMID 10354028.
^ 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 dermatology19 (4): 307-11. PMID 12220273.
^ Fung WK, Lo KK (2000). "Prevalence of skin disease among school children and adolescents in a Student Health Service Center in Hong Kong". Pediatric dermatology17 (6): 440-6. PMID 11123774.
^ Lin RL, Janniger CK (2005). "Pityriasis alba". Cutis; cutaneous medicine for the practitioner76 (1): 21-4. PMID 16144284.
^ Harper J (1988). "Topical corticosteroids for skin disorders in infants and children". Drugs36 Suppl 5: 34-7. PMID 2978289.
^ 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): 152-5. PMID 16792767.
^ 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 : JEADV19 (3): 370-2. PMID 15857470.