Other environmental factors

It has been demonstrated that acne is more common and more severe in industrial and mining areas than in the  countryside.35 The various  explanations  include genetic and dietary factors, and weather differences. It has been demonstrated (see Chapter 12) that increased hydration of the stratum corneum can precipitate acne, which probably accounts for the intensification of acne in certain subjects when the environment  is hot and humid.  Hydration  may be important  in  explaining tropical acne and the occupational acne seen in workers in  kitchens  and  laundries.  It  is  interesting  that Shakespeare's only clinical description of acne was of a kitchen wench:  'Marry,  sir, she's the  kitchen wench and  all grease.' (Comedy  of  Errors,  HI.if).  Several major outbreaks of tropical acne have been described in military personnel. The effect has been attributed to excessive sweating, with the friction of the soldiers' packs contributing to the development of the acne.

 A condition  called acne Majorca, erupting in the spring or summer, has been reported. Forty patients aged 20-40 years presented with domeshaped papules, 1-3  mm in diameter, localized to the acne areas. Pustules and comedones were uncommon. Histology of the condition, which lasted 3-4 months, was  dominated by follicular hyperkeratosis with the formation  of keratinous  cysts, a histological  picture similar to  that  found  in closed comedones. This  cyst occasionally ruptures into the dermis and the sebaceous glands are  usually atrophic.  This disorder  has  been attributed  to heavy exposure to ultraviolet light  and sunscreens, though the role of sunscreens could not be substantiated.39 Exposure  to  sunlight is certainly important, which  may relate to the observation that, in certain patients, acne is worse in the summer.