Antifungal Combinations in Dermatophytes

Dermatophytes are the most common cause of fungal infections worldwide, affecting millions of people annually. The emergence of resistance among dermatophytes along with the availability of antifungal susceptibility procedures suitable for testing antifungal agents against this group of fungi make the combinatorial approach particularly interesting to be investigated. Therefore, we reviewed the scientific literature concerning the antifungal combinations against dermatophytes. A literature search on the subject performed in PubMed yielded 68 publications: 37 articles referring to in vitro studies and 31 articles referring to case reports or clinical studies. In vitro studies involved over 400 clinical isolates of dermatophytes (69% Trichophyton spp., 29% Microsporum spp., and 2% Epidermophyton floccosum). Combinations included two antifungal agents or an antifungal agent plus another chemical compound including plant extracts or essential oils, calcineurin inhibitors, peptides, disinfectant agents, and others. In general, drug combinations yielded variable results spanning from synergism to indifference. Antagonism was rarely seen. In over 700 patients with documented dermatophyte infections, an antifungal combination approach could be evaluated. The most frequent combination included a systemic antifungal agent administered orally (i.e., terbinafine, griseofulvin, or azole-mainly itraconazole) plus a topical medication (i.e., azole, terbinafine, ciclopirox, amorolfine) for several weeks. Clinical results indicate that association of antifungal agents is effective, and it might be useful to accelerate the clinical and microbiological healing of a superficial infection. Antifungal combinations in dermatophytes have gained considerable scientific interest over the years and, in consideration of the interesting results available so far, it is desirable to continue the research in this field.

Systemic antifungal therapy for tinea capitis in children

BACKGROUND

Tinea capitis is a common contagious fungal infection of the scalp in children. Systemic therapy is required for treatment and to prevent spread. This is an update of the original Cochrane review.

OBJECTIVES

To assess the effects of systemic antifungal drugs for tinea capitis in children.

SEARCH METHODS

We updated our searches of the following databases to November 2015: the Cochrane Skin Group Specialised Register, CENTRAL (2015, Issue 10), MEDLINE (from 1946), EMBASE (from 1974), LILACS (from 1982), and CINAHL (from 1981). We searched five trial registers and checked the reference lists of studies for references to relevant randomised controlled trials (RCTs). We obtained unpublished, ongoing trials and grey literature via correspondence with experts in the field and from pharmaceutical companies.

SELECTION CRITERIA

RCTs of systemic antifungal therapy in children with normal immunity under the age of 18 with tinea capitis confirmed by microscopy, growth of fungi (dermatophytes) in culture or both.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 25 studies (N = 4449); 4 studies (N = 2637) were new to this update.Terbinafine for four weeks and griseofulvin for eight weeks showed similar efficacy for the primary outcome of complete (i.e. clinical and mycological) cure in three studies involving 328 participants with Trichophyton species infections (84.2% versus 79.0%; risk ratio (RR) 1.06, 95% confidence interval (CI) 0.98 to 1.15; low quality evidence).Complete cure with itraconazole (two to six weeks) and griseofulvin (six weeks) was similar in two studies (83.6% versus 91.0%; RR 0.92, 95% CI 0.81 to 1.05; N = 134; very low quality evidence). In two studies, there was no difference between itraconazole and terbinafine for two to three weeks treatment (73.8% versus 78.8%; RR 0.93, 95% CI 0.72 to 1.19; N = 160; low quality evidence). In three studies, there was a similar proportion achieving complete cured with two to four weeks of fluconazole or six weeks of griseofulvin (41.4% versus 52.7%; RR 0.92, 95% CI 0.81 to 1.05; N = 615; moderate quality evidence). Current evidence for ketoconazole versus griseofulvin was limited. One study favoured griseofulvin (12 weeks) because ketoconazole (12 weeks) appeared less effective for complete cure (RR 0.76, 95% CI 0.62 to 0.94; low quality evidence). However, their effects appeared to be similar when the treatment lasted 26 weeks (RR 0.95, 95% CI 0.83 to 1.07; low quality evidence). Another study indicated that complete cure was similar for ketoconazole (12 weeks) and griseofulvin (12 weeks) (RR 0.89, 95% CI 0.57 to 1.39; low quality evidence). For one trial, there was no significant difference for complete cure between fluconazole (for two to three weeks) and terbinafine (for two to three weeks) (82.0% versus 94.0%; RR 0.87, 95% CI 0.75 to 1.01; N = 100; low quality evidence). For complete cure, we did not find a significant difference between fluconazole (for two to three weeks) and itraconazole (for two to three weeks) (82.0% versus 82.0%; RR 1.00, 95% CI 0.83 to 1.20; low quality evidence).This update provides new data: in children with Microsporum infections, a meta-analysis of two studies found that the complete cure was lower for terbinafine (6 weeks) than for griseofulvin (6-12 weeks) (34.7% versus 50.9%; RR 0.68, 95% CI 0.53 to 0.86; N = 334; moderate quality evidence). In the original review, there was no significant difference in complete cure between terbinafine (four weeks) and griseofulvin (eight weeks) in children with Microsporum infections in one small study (27.2% versus 60.0%; RR 0.45, 95% CI 0.15 to 1.35; N = 21; low quality evidence).One study provides new evidence that terbinafine and griseofulvin for six weeks show similar efficacy (49.5% versus 37.8%; RR 1.18, 95% CI 0.74 to 1.88; N = 1006; low quality evidence). However, in children infected with T. tonsurans, terbinafine was better than griseofulvin (52.1% versus 35.4%; RR 1.47, 95% CI 1.22 to 1.77; moderate quality evidence). For children infected with T. violaceum, these two regimens have similar effects (41.3% versus 45.1%; RR 0.91, 95% CI 0.68 to 1.24; low quality evidence). Additionally, three weeks of fluconazole was similar to six weeks of fluconazole in one study in 491 participants infected with T. tonsurans and M. canis (30.2% versus 34.1%; RR 0.88, 95% CI 0.68 to 1.14; low quality evidence).The frequency of adverse events attributed to the study drugs was similar for terbinafine and griseofulvin (9.2% versus 8.3%; RR 1.11, 95% CI 0.79 to 1.57; moderate quality evidence), and severe adverse events were rare (0.6% versus 0.6%; RR 0.97, 95% CI 0.24 to 3.88; moderate quality evidence). Adverse events for terbinafine, griseofulvin, itraconazole, ketoconazole, and fluconazole were all mild and reversible.All of the included studies were at either high or unclear risk of bias in at least one domain. Using GRADE to rate the overall quality of the evidence, lower quality evidence resulted in lower confidence in the estimate of effect.

AUTHORS' CONCLUSIONS

Newer treatments including terbinafine, itraconazole and fluconazole are at least similar to griseofulvin in children with tinea capitis caused by Trichophyton species. Limited evidence suggests that terbinafine, itraconazole and fluconazole have similar effects, whereas ketoconazole may be less effective than griseofulvin in children infected with Trichophyton. With some interventions the proportion achieving complete clinical cure was in excess of 90% (e.g. one study of terbinafine or griseofulvin for Trichophyton infections), but in many of the comparisons tested, the proportion cured was much lower.New evidence from this update suggests that terbinafine is more effective than griseofulvin in children with T. tonsurans infection.However, in children with Microsporum infections, new evidence suggests that the effect of griseofulvin is better than terbinafine. We did not find any evidence to support a difference in terms of adherence between four weeks of terbinafine versus eight weeks of griseofulvin. Not all treatments for tinea capitis are available in paediatric formulations but all have reasonable safety profiles.

Tinea capitis: a treatment update

Currently, many experts consider griseofulvin to be the drug of choice for tinea capitis. It is FDA approved for this indication, highly efficacious, and has an excellent long-term safety record. Nonetheless, there is now ample evidence documenting the efficacy and safety of other antifungal agents. Terbinafine, itraconazole, and fluconazole have been used off-label in the United States and United Kingdom for tinea capitis. Several studies have shown that short-term terbinafine, itraconazole, or fluconazole each are comparable in efficacy and safety to griseofulvin. High-dose griseofulvin is still the first-line therapy for tinea capitis in our practice, but a large-scale, multicenter trial of higher dose terbinafine is now ongoing, and positive efficacy and safety results from that study may lead to a change in our standard of care. Terbinafine, itraconazole, or fluconazole currently are used in patients who have either failed griseofulvin or developed adverse reactions to this medication. Families must be informed that these other antifungal agents are not FDA-approved for this indication when they are used. Guidelines for therapy with each of these agents are summarized in Table 5. In addition, the adjuvant use of antifungal shampoos is recommended for all patients in order to decrease the viability of fungal spores present on the hair, as well as for all household contacts to prevent infection or eliminate the carrier state.

Itraconazole in the treatment of tinea capitis caused by Microsporum canis: experience in a large cohort

Mycotic scalp infection caused by Microsporum canis is one of the more recalcitrant disorders, with increasing incidence during the last decade. We report our experience with administration of itraconazole in 163 children (86 girls, 77 boys) with M. canis tinea capitis. Fifty-five patients had previous treatment with terbinafine without success. In all children, the dosage of itraconazole was adjusted according to body weight, with 5 mg/kg/day given in a continuous regimen either as a capsule (116 patients) or an oral suspension (47 patients). In all children, there was both clinical and mycologic cure after a mean treatment period of 39 +/- 12 days (range 10-77 days). Eleven children (6.7%) had side effects: diarrhea in five children, cutaneous eruption in four, and abdominal pain in two. Itraconazole was effective and safe for the treatment of M. canis tinea capitis.