75 ISSN 1745-5111 Pediatric Health (2009) 3(1), 75–79 10.2217/17455111.3.1.75 © 2009 Future Medicine Ltd required for the production of melanin; hence, copper deficiency may in effect play a role in the pathogenesis of PA [1,6,7] . Since 1956, when O’Farrell suggested that PA could be considered a form of eczematous dermatitis [8] , it has been widely considered as a mild form of atopic dermatitis [9] . With regard to this, it is not surprising that other possible favor- ing factors of PA may be sun exposure without sunscreens, frequent and hot baths, wind, soaps and cutaneous xerosis [7,9] . Clinical features The individual lesion of PA is characterized by a rounded, oval or irregular plaque of a pale pink color. Furfuraceous or branny scal- ing covers the patch. One or several patches could be found with a diameter varying from 0.5 to 5 cm. Most lesions appear on the face, but upper extremities and the trunk may also be involved. Forehead and malar ridges are mainly involved in 63 and 57% of the cases, respectively. Angles of mouth and lateral super- orbital regions are less involved, observed in 37 and 35% of patients, respectively. Only in 20% of affected children are symptoms present on the neck, shoulders or trunk as well as the face [1,10] . Once a pink patch with elevated borders has formed, PA usually fades over several weeks into a white patch covered with a powdery scale that can persist for months or years. Often erythema is so pale and of short course that it is unnoticeable. The lesions become more notable in summer with tanning of the sur- rounding skin. Recurrent crops of new lesions may develop at intervals. Pityriasis alba (PA) is a common cutaneous disorder characterized by asymptomatic hypo- pigmented patches on the face, neck, trunk and proximal extremities of children and young adults. The single lesion has sharply demar- cated margins and is covered by a fine branny scale (FIGURE 1) . The cause of PA is still unknown, but the condition is widely considered as a mild form of atopic dermatitis. It often appears after sun exposures and result as a lack of pigmenta- tion probably owing to a difficulty in pigmen- tation in the scaly hyperkeratotic patches. Lack of sunscreen use and frequent baths are also frequently reported. Epidemiology Pityriasis alba is found all over the world. It is quite common, affecting between 1.9 and 5.25% of preadolescent children. The peak of incidence is between the ages of 6 and 12 years [1] . It is more often observed in atopic subjects (77.9%) than in the general population [2] . Both sexes are equally susceptible. PA has a high prevalence in infants and children of low socioeconomics con- ditions in developing countries, being present in 12–90% of children [3–5] . Etiology & pathogenesis Streptococcus β haemoliticus and Staphylococcus aureus infections, nutritional deficiencies and parasitic infections have been called out to explain the etiology of PA, but no definitive asso- ciations have been demonstrated, even if these disorders appear to be more frequent in patients with PA. Iron and copper deficiency have been described in patients with PA. In particular, copper is a cofactor for tyrosinase, an enzyme Review Infantile pityriasis alba and comorbid disorders Elisa Guareschi & Vito Di Lernia † Pityriasis alba is a common cutaneous disorder characterized by asymptomatic hypopigmented patches on the face, neck, trunk and proximal extremities of children and young adults. Its pathogenesis has not been definitely clarified. Pityriasis alba is considered to be a low-grade eczematous dermatitis and is regarded as a minor feature of atopic dermatitis. Possible comorbid disorders described in association with pityriasis alba are nutritional deficiency, anemia and parasitic infestations; however, these are exclusively observed in children of poor socioeconomic conditions. In the past, a pathogenic implication of several microorganisms, in particular Gram-positive bacteria, has repeatedly been proposed but never confirmed. Pityriasis alba has no reliable treatment, but it usually resolves with time. Emollients, mild topical steroids and pimecrolimus may aid to accelerate the repigmentation. † Author for correspondence Struttura Complessa di Dermatologia, Arcispedale Santa Maria Nuova, Azienda Ospedaliera di Reggio Emilia, viale Risorgimento 80, 42100 Reggio Emilia, Italy Tel.: +39 522 296 873/564 Fax: +39 522 295 708 vito.dilernia@asmn.re.it Keywords atopic฀dermatitis฀•฀hypochromic฀ patches฀•฀hypomelanosis฀ •฀pityriasis฀alba฀•฀pityriasis฀ alba extensa part of For reprint orders, please contact: reprints@futuremedicine.com