Tissue immunostaining for factor XIIIa in dermal dendrocytes of pityriasis alba skin lesions.
BACKGROUND
Pityriasis alba affects 1% of the world population and about 9.9% of the children in Brazil. However, its etiology remains uncertain.


OBJECTIVE
The objective of the present study was to evaluate the immunoexpression of factor XIIIa in dermal dendrocytes of skin lesions of pityriasis alba.


METHODS
Twenty patients with pityriasis alba and 20 patients with atopic dermatitis underwent biopsy. The dermal dendrocytes marked by factor XIIIa were counted by means of immunohistochemical analysis.


RESULTS
The mean amount of dermal dendrocytes found in the patients with pityriasis alba was 2, whereas in the patients with atopic dermatitis it was 4, with a statistically significant difference between them. A cutoff point of 3 cells/square inch was established to differentiate pityriasis alba from atopic dermatitis, with 80% sensibility and 90% specificity.


CONCLUSIONS
We believe that pityriasis alba and atopic dermatitis should be considered different clinical forms within the spectrum of atopic disease, in which sun radiation plays an important role by modulating the progression of the disease.
Universidade do Estado do Pará, Belém, PA, Brazil.
Francisca Regina Oliveira
FR
Carneiro
Universidade do Estado do Pará, Belém, PA, Brazil.
Gabriela Borborema do
GB
Amaral
Universidade do Estado do Pará, Belém, PA, Brazil.
Maiana Darwich
MD
Mendes
Universidade do Estado do Pará, Belém, PA, Brazil.
Juarez Antônio Simões
JA
Quaresma
D001706:Biopsy; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000473:pathology*; D018450:Disease Progression; D026122:Factor XIIIa / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000473:pathology*; D008297:Male; D010915:Pityriasis / Q000473:pathology*; D012372:ROC Curve; D012867:Skin / Q000473:pathology; D018709:Statistics, Nonparametric
D026122:Factor XIIIa