[Basic principles in local dermatologic therapy]

The vehicle or ointment base plays an important role in dermatological local treatment. This is true from a therapeutic point of view and with respect to quality of life as well. Vehicles exert pronounced effects on the epidermis; these effects include hydration, lubrication, drying, skin smoothness, occlusion and protection. The vehicle controls the release and penetration, and ultimately the bioavailability, of the dermatological active ingredients. An overly simplified rule of thumb is that a deep-layer effect is enhanced by increasing occlusion. Unfortunately, no uniform classification system exists. Frequently, users of topical applied products are confused by the non-uniform, and in some cases erroneous, vehicle designations. In particular, different names are used to describe the lipophilic emulsion systems. It would be important to consistently use the official designations here: hydrophilic cream or lipophilic (hydrophobic) cream or ointment. Dermatological pastes are also often misleading designated, without any further distinctions, as a uniform occlusive system. For practical applications, attention must be paid in particular to the different indications for hydrophilic and lipophilic vehicles. Hydrophilic, aqueous bases are to be used for acute lesions and seborrhoeic skin, fatty or oily lipophilic systems for dry hyperkeratotic lesions and sebostatic skin. The cosmetic acceptance of a vehicle has a direct impact on both compliance and therapeutic effect. More attention should be paid to these factors. Adverse reactions caused by single components of the vehicle are not unusual. If a lesion does not respond to local treatment, the diagnosis should be reconsidered; moreover, the vehicle and its components should be investigated for possible incompatibility reactions.