Lithium succinate and seborrhoeic dermatitis: an antifungal mode of action?

Precipitation of free fatty acids generated by Malassezia - a possible explanation for the positive effects of lithium succinate in seborrhoeic dermatitis

BACKGROUND

Lithium succinate and gluconate are effective alternative options licensed for the topical treatment of seborrhoeic dermatitis (SD).

OBJECTIVE

Their mode of action is not fully elucidated. Minimal inhibitory concentrations against Malassezia (M.) yeasts, which play an important role in SD, are very high.

METHODS

An assay based on the hydrolysis of ethyl octanoate enables us to test the hydrolytic activity of reference strains of the species M. globosa, M. sympodialis and M. furfur solely without interference by fungal growth as the free octanoic acid generated has antifungal activity.

RESULTS

In this assay the presence of alkali salts (lithium, sodium and potassium succinate resp.) in concentrations of 2%, 4% and 8% does not influence hydrolytic activity but the availability of the generated free fatty acid in a dose-dependent manner which was analysed by means of high-performance thin layer chromatography and densitometry. This was best effected with the lithium, followed by the sodium and only to a low degree by the potassium salt. As shown by attenuated total reflection Fourier transform infrared spectroscopy the free fatty acid reacted to the respective alkali soap and precipitate from solution. The alkali soaps could not be utilized by the M. spp. as shown in a modified Tween auxanogram and in lack of fungal growth by ethyl oleate in the presence of 8% lithium succinate.

CONCLUSION

The effect of lithium succinate on growth of M. yeasts and presumably in SD can be explained by a precipitation of free fatty acids as alkali soaps limiting their availability for the growth of these lipid-dependent yeasts.

Anti-inflammatory effects of lithium gluconate on keratinocytes: a possible explanation for efficiency in seborrhoeic dermatitis

Topical lithium (Li) gluconate has a beneficial effect on seborrhoeic dermatitis (SD), unlike oral lithium (Li) used in psychiatry. SD is an inflammatory dermatitis associated, in most of cases, with colonization by lipophilic yeasts of the genus Malassezia. However, the exact mechanism of action of Li gluconate in SD still remains unknown. The aim of our study was to investigate the effect of topical Li on cytokine secretion and innate immunity. For this purpose, we investigated first the modulatory effect of Li on two pro-inflammatory and two anti-inflammatory cytokine secretion and second, the modulatory effect of Li on Toll-like receptor (TLR) 2 and 4 expression by unstimulated and stimulated keratinocytes. Two different skin models were used: keratinocytes in monolayer and skin explants. In some of them, inflammation was induced with LPS (1 mug/ml) or zymosan (2 mg/ml). Then the skin models were incubated with Li gluconate (Labcatal*, Montrouge, France) at three different concentrations (1.6, 3, 5 mM) determined according to viability MTT test. Expression of TNFalpha, IL6, IL10, TGFbeta1, TLR2 and TLR4 was detected by immunohistochemistry (IHC). Cytokines were quantified by ELISA methods. Our results showed that the effect of Li on keratinocytes is dose-dependent. At low concentration (1.6 mM), Li enhanced TNFalpha secretion, whereas, at higher concentration (5 mM), Li significantly enhanced IL10 expression and secretion. However, there was no significant modulation of Li on IL6 and TGFbeta1 secretion. Moreover, Li at 5 mM significantly decreased TLR2 and TLR4 expressions by differentiated keratinocytes. As Li concentration during topical treatment is probably closer to 5 mM than to 1 mM, the therapeutic effect of Li gluconate in DS may be explained by two anti-inflammatory actions: an increased expression and secretion of IL10 and a decreased expression of TLR2 and TLR4 by keratinocytes. The diminution of TLR2 expression by Li may not allow MF to trigger inflammation response in lesional skin.

Seborrhoeic dermatitis: current treatment practices

Seborrhoeic dermatitis (SD) is a recurrent, chronic inflammation of the skin that occurs on sebum rich areas such as the face, scalp and chest, characterised by red scaly lesions. The are many studies indicating that Malassezia yeasts play an important role in the aetiology of this condition, most of the evidence for which comes from demonstrated responsiveness to treatment with antifungal agents. Its aetiology, however, is far from being resolved. Some believe that it is the immune response of the skin to the Malassezia that is the cause of the disease. Traditional treatments of SD have been the use of keratolytic agents or corticosteroids. Since the discovery of ketoconazole, a considerable amount of research has been focused on determining the efficacy of various antifungal agents. This article reviews clinical trial data on treatment options available for SD.

Lithium

The mode of action of the cation lithium is not well known. It is at present used as a topical drug in dermatology. Lithium inhibits many enzymes: Na/K ATPase, adenylcyclase, enzymes of the prostaglandines E1 synthesis, inositol-1-phosphatase. It is active on neutrophils et T lymphocytes, explaining in part its anti-inflammatory activity. It has a dose-dependent action on levures. It has possibly a direct inhibitory activity on DNA synthesis of herpes viruses. Lithium has a good local safety. Percutaneous penetration is weak and plasma concentrations are very much lower than that observed after oral intake. Lithium has been studied in seborrhoeic dermatitis. Its efficacy was primarily observed in psychotic patients. An assay with oral lithium did not confirmed the first observations. Topical lithium was found more efficient. Topical lithium succinate associated with zinc sulfate and lithium gluconate had a greater efficacy than placebo. Comparison with topical ketoconazole showed a non inferiority of lithium gluconate. Oral lithium also showed a reduction of symptoms' duration of herpes simplex. Cutaneous side-effects of oral lithium are frequent and numerous. Some of them may be explained by a lithium pharmacological cell activity (such as psoriasis). Teratogenicity is observed in mice and rats. Drug interactions are not expected after topical application. Irritants side effects are mainly observed after topical application; they are moderate and transitory. Lithium gluconate treatment of seborrhoeic dermatitis is a bid application during at least 8 weeks. It may be used in renal insufficiency. It is not recommended in the first trimester of pregnancy.

Seborrheic dermatitis

Seborrheic dermatitis is a common inflammation of the skin, occurring most often on the face, scalp and chest. It is closely related to infantile seborrheic dermatitis, or diaper rash. Seborrheic dermatitis is particularly common in patients with Parkinson's disease or with HIV/AIDS. The recent resurgence of interest in Malassezia yeasts has revived the old hypothesis that seborrheic dermatitis is caused by an altered relationship between these skin commensals and the host. Moreover, the success of antifungal medications in treating seborrheic dermatitis provides new evidence for this view.

LEARNING OBJECTIVE

Upon completing this paper, the reader should be aware of the clinical presentation of seborrheic dermatitis and which populations are at particular risk of developing this disorder. In addition, s/he will be aware of the role of Malassezia yeasts in seborrheic dermatitis and the way in which knowledge of the importance of these yeasts has altered the treatment of this disorder.

Seborrheic dermatitis

Seborrheic dermatitis is present in 1% to 3% of immunocompetent adults, and is more prevalent in men than in women. Seborrheic dermatitis may be seen in conjunction with other skin diseases, such as rosacea, blepharitis or ocular rosacea, and acne vulgaris. Malassezia yeasts have been associated with seborrheic dermatitis. Abnormal or inflammatory immune system reactions to these yeasts may be related to development of seborrheic dermatitis. Treatment modalities for seborrheic dermatitis include keratolytic agents, corticosteroids, and more recently, antifungal agents. Antifungal agents do not carry a risk of skin atrophy or telangiectasia with prolonged use, and it is more prudent to consider antifungals than corticosteroid preparations. The wide range of antifungal formulations available (creams, shampoos, or oral) provides safe, effective, and flexible treatment options for seborrheic dermatitis.

Lithium gluconate 8% vs ketoconazole 2% in the treatment of seborrhoeic dermatitis: a multicentre, randomized study

BACKGROUND

Lithium significantly improved seborrhoeic dermatitis symptoms in comparison with placebo. Objectives This randomized controlled trial was designed to show a non-inferiority of 15% (primary end-point) of lithium gluconate 8% ointment compared with ketoconazole 2% emulsion.

METHODS

The study population comprised out-patients who had facial seborrhoeic dermatitis for at least 2 months, with moderate to severe erythema and desquamation at inclusion. The primary end-point was complete remission, defined as the disappearance of both erythema and desquamation. The non-inferiority of lithium was assessed on the 95% confidence interval (CI) of the difference between treatments.

RESULTS

The intent-to-treat analysis (ITT) involved 288 patients and the per protocol (PP) analysis 269 patients. Treatment groups were comparable at baseline on age, sex, disease duration and symptoms. For the main criterion, the success rate was 52.0% (lithium) vs. 30.1% (ketoconazole) in the ITT population and 53.2% (lithium) vs. 30.7% (ketoconazole) in the PP population. The non-inferiority of lithium was demonstrated with differences of 21.9% (95% CI 10.0-33.7%) and 22.5% (95% CI 10.2-34.8%), respectively, in the ITT and PP population. As the lower limit of the 95% CI was > 0, the superiority of lithium was shown. Lithium also showed better results on other symptoms: burning and dryness. Adverse events were reported by 26.3% (lithium) and 25% (ketoconazole) of patients.

CONCLUSIONS

Lithium was 22% more effective than ketoconazole in giving complete remission of seborrhoeic dermatitis, with comparable safety.

A double-blind, placebo-controlled, multicenter trial of lithium succinate ointment in the treatment of seborrheic dermatitis. Efalith Multicenter Trial Group

BACKGROUND

Seborrheic dermatitis, an inflammatory dermatosis that principally affects sebaceous areas, may be related to the presence of the yeast Pityrosporum ovale. Topical therapy with corticosteroids, although in general effective, may be associated with several unwanted effects. The development of alternative non-steroid-based therapies may enable patients to avoid the use of topical steroids and help elucidate the pathogenesis of the disease.

OBJECTIVE

This study aimed to assess the efficacy and safety of an ointment containing 8% lithium succinate in the treatment of seborrheic dermatitis.

METHODS

The study consisted of a multicenter placebo-controlled clinical trial in 227 adult patients.

RESULTS

Lithium succinate ointment was significantly more effective than placebo in treating all the symptoms of seborrheic dermatitis. No specific unwanted effects were associated with its use. Relapse was slow when treatment was stopped.

CONCLUSION

The effectiveness of lithium succinate ointment in the treatment of seborrheic dermatitis adds to the evidence implicating P. ovale in the pathogenesis of that condition.