Improved topical treatment of lamellar ichthyosis: a double-blind study offour different cream formulations

Lamellar ichthyosis (LI) is characterized by generalized scaling of the ski n and is often resistant to ordinary emollients. Recently, Locobase(R) fatt y cream containing a mixture of 5% lactic acid and 20% propylene glycol (LP L) was found to be markedly effective in a pilot study. To consolidate this finding, a double-blind study comparing Lm, with the corresponding mixture in Essex(R) (Diprobase(R)) cream (LPE) and Locobase(R) fatty cream contain ing either 5% urea or 20% propylene glycol was conducted in 20 patients wit h LI. Before and after applying the creams twice daily on each of the four extremities for 4 weeks, the following investigations were performed: scori ng of xerosis, scaling and erythema, measurements of skin hydration (capaci tance) and transepidermal water loss (TEWL). and moulding of the skin surfa ce (replicas). Xerosis was reduced by all four creams, but significantly mo re so by LPL (P < 0.001) and LPE (P < 0.01). Scaling was only reduced by LP L (P < 0.001) and LPE (P < 0.01), which also caused a slight increase in th e erythema score (P < 0.05 for both), The patients' weekly evaluation of sy mptoms showed that LPL produced the most rapid effect: the response rate af ter 4 weeks was 63%. Skin hydration and TEWL were both significantly increa sed by LPL and LPE, whereas skin roughness was reduced most by LPL. Fourtee n patients preferred LPL over the other cream formulations, Ten patients co ntinued using LPL for up to 8 weeks with good results and no side-effects o ther than occasional irritation in the skin folds. LPL is a major advance i n thr topical treatment of LI that suits most patients. Some patients, howe ver, seem to prefer the more hydrophilic LPE formulation. Both formulations effectively reduce hyperkeratosis and xerosis, but mag cause slight irrita tion and adversely affect the epidermal barrier function.