1. A body or hair cleansing composition comprising (a-1) a ketoconazole or elubiol as a first active ingredient, (a-2) a pyrithione salt as a second active ingredient, and (b) art-known body or hair cleansing product ingredients as a carrier, wherein the first active ingredient is present in quantities producing a mutual synergistic effect on t he inhibition of the growth of dermatophyte fungi. 2. A composition according to claim 1 wherein pyrithione salt is zinc pyrithione or sodium pyrithione. 3. A composition according to claim 2 wherein the first active ingredient is present in an amount ranging from about 0.1 % to about 2 % (w/w) and the second active ingredient is present in an amount ranging from about 0.05 % to about 2 % (w/w), the amount of the latter being expressed as weight of zinc pyrithione. 4. A composition according to any one of the preceding claims formulated as a shampoo. 5. A composition according to claim 4 wherein the art-known shampoo ingredients comprise one or more of a surfactant, a foaming agent, a thickener sufficient to give the final formulation a viscosity in the range of 4,000 to 9,000 mPa.s at room temperature, a preservative, an anti-oxidant, and acid or base or buffer sufficient to give the shampoo a pH in the range of from about 4 to about 10. 6. A composition according to claim 5 comprising one or more surfactants selected fr om the group comprising sodium C14-16 olefin sulfonates, sodium lauryl sulfate, sodium laureth sulfate, cocamidopropylamine oxide, lauryl amine oxide, lauramido DEA, cocamidopropyl betaine, lauryl dimethyl betaine, cocodimethyl sulphopropyl betaine, sodium cocoyl sarcosinate, disodium oleamido MIPA sulfosuccinate, disodium cocamido MIPA sulfosuccinate, disodium laureth sulfosuccinate, cocoamphocarboxy-glycinate, disodium oleamido MEA sulfosuccinate, amine glycinates, amine propionates and amine sultaines, and mixtures thereof. 7. A compound according to claim 5 wherein the foaming agent is selected from the group of fatty acid mono- and di- alkanolamides consisting of cocamide MEA, cocamide DEA, oleamide MEA, oleamide DEA and mixtures thereof. 8. A compound according to claim 5 wherein the antioxidant is butylated hydroxytoluene or butylated hydroxyanisole employed in an amount of about 0.01 to about 1% (w/w). 9. A compound according to claim 5 further comprising a conditioner. 10. A compound according to claim 5 further comprising one or more pearlizing agents selected from the group consisting of ethylene glycol distearate, ethylene glyco monostearate and mixtures thereof. 11. A composition according to claim 5 further comprising one or more fragrances and one or more colorants. 12. A process for preparing a shampoo formulation as defined in any one of the preceding claims comprising the steps of: (a) heating a solution of thickener and deionized water, (b) mixing the surfactants, the foaming agent and optionally the pearlizing agent with the solution of (a), (c) mixing the BHT with the solution of (b), (d) mixing the antifungal with the solution of (c), (e) dispersing the pyrithione salt in the mixture of (d), (f) allowing the suspension of (e) to cool somewhat and mixing therewith the preservative(s), the sodium chloride for thickening to the required viscosity, and optionally the conditioner, the fragrance(s) and colorant(s), (g) adding acid, base or buffer to the solution of (f) to yield a pH in the rang e of 4 to 10, and (h) adding deionized water to the solution of (g) to 100%.