This type of acne is more commonly encountered in the USA than in the UK . A study has investigated 735 black patients of whom 70 per cent regularly used pomades. Pomade acne presents as a recognizable acneiform eruption seen on the forehead and temple and consisting mainly  of uniform closed comedones, with occasional papules and pustules.  Histologically this 'pomade acne' is indistinguishable from ordinary comedonal acne.

  Another study found that a minor form of acne was prevalent in one-third of American females in the age range 20-50 years, especially between the ages of 20 to 30 years. It was suggested that cosmetics were the cause of the eruption.  The lesions were found to be situated predominantly around the mouth and consisted of small comedones,  although small papules and  pustules might also arise erratically. Premenstrual exacerbations and seborrhoea were not a feature of this group. However, a history of severe acne  in the patient was associated with a greater degree of severity of this  type of acne. This is perhaps not surprising since it is known that an  enhanced sebum excretion rate persists even though 'teenage' acne has regressed. Twenty-five commonly used cosmetic creams were then investigated, using both a rabbit ear model and topical application in adult volunteers (for up to six weeks). Thirteen of the creams  investigated were found to be comedogenic. Lanolin, petrolatum and certain vegetable oils, as well as pure chemicals such as butyl stearate, lauryl alcohol and oleic acid were all comedogenic; oleic  acid  is present in significant amounts in sebum.

  In the UK cosmetics  have not been identified as a major reason for the persistence of  acne. The relationship between the number of hours for which cosmetics have been used and acne severity and there is no correlation. Also, if cosmetics are important for  acne,  then the greater  the  use of cosmetics the higher the ratio of acne severity on the face compared to the trunk; this is not so.

  In the USA, cosmetic houses list products which are noncomedogenic,  as determined  in animal  experiments; switching to noncomedogenic cosmetics helps but  does  not  however  bring  about rapid  clinical changes.  Topical  retinoic acid is  the best treatment since many of the early lesions in cosmetic and pomade acne are comedones. Acne detergicans Yet another type of externally induced acne has been demonstrated  in  patients  who  obsessively  wash themselves very frequently - at least four times a day. Clinical observations were supported by showing that, in the rabbit  ear, several common brands  of soap, applied in a 25 per cent concentration, induced comedones.