A Double Blind Randomized Trial, Placebo-controled of 0.0003% Calcitriol Ointment Versus 0.1% Tacrolimus Ointment in the Treatment of Pityriasis Alba

Pityriasis alba (PA) is a benign inflammatory dermatosis affecting about 5% of infantile population, frequently seen in tropical areas of the world. This entity has received many synonymous such as chronic impetigo and erythema streptogenes, but its actual name was given from Hazen. PA is also considered a minor criterion for the diagnosis of atopic dermatitis. It is characterized by hypopigmented, irregular plaques with well-defined borders, covered by fine scales; it affects mainly face, limbs and occasionally thorax.

Its etiology is still unknown, although infectious mechanisms and vitamin and minerals deficiencies have been implicated, a causal relationship has not been recognized. However, excessive and unprotected sun exposure is considered the most important causal factor involved. However, studies from stratum corneum from of PA lesions have described defects in hygroscopicity and water-holding capacity detectable by water sorption-desorption test, this suggests that the condition is similar to a dermatitic change and its hypopigmentation may be consequence of a postinflammatory mechanism.

The study population will include at least 20 lesions in individuals with phototype IV-V, affected symmetrically by PA on the face. Their selected age will be less than 18 years. Patients with other dermatoses, including atopic dermatitis, use of any systemic or topical medication during the past 4 weeks will be excluded. Informed consent was obtained from the parents and children before entering the study, which was approved by the local ethical committee (Institutional Review Board).

Patients will be randomly assigned in a double-blind manner to receive on the lesions 0.0003% calcitriol (Galderma, France), 0.1% tacrolimus (Astellas, Pharma, USA), and petrolatum (Aquaphor ointment)in all of them. All subjects were instructed to apply the treatment twice daily. Sunscreen will not be indicated, and hygienic habits are not being changed. Hypopigmented areas are going to be initially evaluated and supervised at 3, 6 and 9 weeks. Digital photographic registration(frontal, right, and left views) with an SLR Fuji FinepixS1pro camera will be taken and analysed by ImageJ software to quantify the reduction area of the plaques. The methods of assessment involve clinical evaluation by investigators, an independent observer, and by the transepidermal water loss (TEWL) with an evaporimeter (Dermalab, Cortex Technology, Denmark), and pigmentary changes using a colorimeter (Chromameter CR-300, Minolta, Osaka, Japan). Water loss will be recorded on each plaque for 60 seconds, as well as the L* (luminosity) and a* (erythema) axis. All adverse effects will be recorded. Statistical analysis was performed using T student, the level of significance was set at 5%. And clinical evaluation will be analysed by means of chi square tests.