Evening primrose oil (Epogam) in the treatment of chronic hand dermatitis: disappointing therapeutic results.
BACKGROUND
Hand dermatitis is a common therapeutic challenge with limited and unsatisfactory therapy modules. A possible beneficial role of oral evening primrose oil needs to be investigated.


OBJECTIVE
Pharmacological doses of gamma-linolenic acid (GLA) could improve the water permeability barrier of the epidermis in chronic hand dermatitis. Clinical improvement, changes in the lipogram and epidermal lipid composition could define functional improvement of the skin. Electron-microscopic evaluation of the epidermal lipid bilayer could underline the efficacy of essential fatty acids in chronic hand dermatitis.


METHODS
Thirty-nine patients with chronic (> 1 year), stable hand dermatitis entered a 24-week double-blind placebo-controlled trial. Patch test with the European standard of allergens, haematogram and serum IgE values were determined before commencement of the study. Active therapy (600 mg/day of GLA) was administered to half the patient group. Medication was given for 16 weeks and observations continued for another 8 weeks. Patients were assessed clinically, using a visual analogue scale at 4-week intervals. Plasma and red blood cell lipograms, as well as skin biopsies, were taken before therapy, after the 16-week supplementation period and at week 24. Tissue was used for histological evaluation, electron-microscopic assessment and epidermal lipid analysis.


RESULTS
Improvement in clinical parameters was present in the Epogam and placebo groups, but no statistical difference could be confirmed between the groups. Haematogram, blood and epidermal biochemistry were normal at baseline. No change in the lipid composition of plasma red cells or epidermis could be detected during the trail. Ultrastructurally skin specimens showed no change during the study period.


CONCLUSIONS
The study indicates that the therapeutic value of orally administered GLA for chronic hand dermatitis is not superior to that of placebo.
Whitaker
D K
DK
Department of Dermatology, University of Stellenbosch, Tygerberg, Republic of South Africa.
Cilliers
J
J
de Beer
C
C
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D002908:Chronic Disease; D003879:Dermatologic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004912:Erythrocytes / Q000378:metabolism; D005228:Fatty Acids, Essential / Q000008:administration & dosage / Q000378:metabolism / Q000627:therapeutic use*; D006229:Hand Dermatoses / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008041:Linoleic Acids; D008051:Lipid Bilayers / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008854:Microscopy, Electron; D008875:Middle Aged; D031665:Oenothera biennis; D010539:Permeability; D010919:Placebos; D010938:Plant Oils; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D014867:Water; D017965:gamma-Linolenic Acid / Q000008:administration & dosage / Q000627:therapeutic use
D000894:Anti-Inflammatory Agents, Non-Steroidal; D003879:Dermatologic Agents; D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D008051:Lipid Bilayers; D008055:Lipids; D010919:Placebos; D010938:Plant Oils; D014867:Water; C028498:evening primrose oil; D017965:gamma-Linolenic Acid