Different effects of pimecrolimus and betamethasone on the skin barrier in patients with atopic dermatitis.
BACKGROUND
Genetic defects leading to skin barrier dysfunction were recognized as risk factors for atopic dermatitis (AD). It is essential that drugs applied to patients with AD restore the impaired epidermal barrier to prevent sensitization by environmental allergens.


OBJECTIVE
We investigated the effect of 2 common treatments, a calcineurin inhibitor and a corticosteroid, on the skin barrier.


METHODS
In a randomized study 15 patients with AD were treated on one upper limb with pimecrolimus and on the other with betamethasone twice daily for 3 weeks.


RESULTS
Stratum corneum hydration and transepidermal water loss, a marker of the inside-outside barrier, improved in both groups. Dye penetration, a marker of the outside-inside barrier, was also reduced in both drugs. Electron microscopic evaluation of barrier structure displayed prevalently ordered stratum corneum lipid layers and regular lamellar body extrusion in pimecrolimus-treated skin but inconsistent extracellular lipid bilayers and only partially filled lamellar bodies after betamethasone treatment. Both drugs normalized epidermal differentiation and reduced epidermal hyperproliferation. Betamethasone was superior in reducing clinical symptoms and epidermal proliferation; however, it led to epidermal thinning.


CONCLUSIONS
The present study demonstrates that both betamethasone and pimecrolimus improve clinical and biophysical parameters and epidermal differentiation. Because pimecrolimus improved the epidermal barrier and did not cause atrophy, it might be more suitable for long-term treatment of AD.
Department of Dermatology, University of Kiel, Kiel, Germany.
Jens-Michael
JM
Jensen
Stephan
S
Pfeiffer
Magdalena
M
Witt
Matthias
M
Bräutigam
Claudia
C
Neumann
Michael
M
Weichenthal
Thomas
T
Schwarz
Regina
R
Fölster-Holst
Ehrhardt
E
Proksch
D000279:Administration, Cutaneous; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001623:Betamethasone / Q000627:therapeutic use*; D003876:Dermatitis, Atopic / Q000188:drug therapy* / Q000276:immunology; D003879:Dermatologic Agents / Q000627:therapeutic use*; D004817:Epidermis / Q000187:drug effects / Q000276:immunology* / Q000648:ultrastructure; D006801:Humans; D046529:Microscopy, Electron, Transmission; D012869:Skin Absorption; D016559:Tacrolimus / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014870:Water Loss, Insensible / Q000502:physiology
D000893:Anti-Inflammatory Agents; D003879:Dermatologic Agents; C117268:pimecrolimus; D001623:Betamethasone; D016559:Tacrolimus