Psoriasis: flexural and genital psoriasis

This chapter discusses the management of psoriasis affecting the flexures and genitalia and is set out as follows:

• It is always important to ask if patients have genital involvement as they may not otherwise come forward with the information - genital involvement can be very uncomfortable and can interfere with relationships

Flexural psoriasis 

• Distribution
• Several sites can be affected including the axillae, under the breasts, umbilicus, groins, gluteal cleft (between the buttocks), around the anus, penis / scrotum and the vulva

• Morphology
  • Lesions in the flexures are usually symmetrical, very shiny, red and well-demarcated
  • As a result of friction, significant scale if often lacking. If affected areas are, however, asymmetrical and scale is present always consider tinea and send scrapings for mycology

Genital psoriasis 

• The vulva - often appears as smooth, non-scaly and red areas. Scratching this area may cause an infection, produce dryness, and result in thickening of the skin and further itching

• The penis - often appears as many small, red patches on the glans, or shaft. The skin may be scaly or smooth and shiny

• Emollients
   
• Topical steroids
• ​The skin on flexural sites and the genitalia is relatively thin and so topical steroids no stronger than Eumovate ® cream are recommended
• In cases of co-existent yeast a combination product such as Trimovate ® cream should be used
• Treatment with topical steroids should be discontinued once symptoms settle
• The overuse of topical steroids in body folds may cause striae and can result in long-term aggravation of psoriasis (tachyphylaxis)

• If there are concerns that too much topical steroid is being used it can be worth trying a vitamin-D compound such as Curatoderm ® lotion / ointment or Silkis ® ointment. Another option are the calcineurin inhibitors Elidel ® (pimecrolimus) cream or Protopic ® (tacrolimus) ointment, although both are off-label in psoriasis

• The skin on the gluteal cleft is thicker than on the other sites and if necessary more potent topical steroids can be used periodically if needed