The present invention provides a foamable composition for administration to the skin, body surface, body cavity or mucosal surface, e.g., the mucosa of the nose, mouth, eye, ear, respiratory system, vagina or rectum, and methods of using such a composition to treat, alleviate, or prevent a disorder of the skin, body cavity, or mucosal surface. The foamable oil in water nano emulsion composition includes: (a) a nano oil globule system, comprising substantially of sub-micron oil globules; (b) about 0.1% to about 5% by weight of at least one stabilizing agent selected from (i) a non-ionic surfactant, (ii) an ionic surfactant, or (iii) a polymeric agent; and (c) a liquefied or compressed gas propellant at a concentration of about 3% to about 25% by weight of the total composition, water and optional ingredients. Upon release from an aerosol container, the foamable composition forms and expanded foam suitable for topical administration.