INTRODUCTION
Patients with psoriasis commonly have involvement of the skin fold areas referred to as intertriginous, exural, or inverse psoriasis.These areas are typically marked by less epidermal keratinization and include the axillae, perianal skin, antecubital fossae, popliteal fossae, intergluteal cleft, inframammary, genital/inguinal, abdominal, and retroauricular folds.1 According to the Nurses Health Study and Health Professionals Follow-up Study, the frequency of inverse psoriasis among physician-diagnosed psoriasis is 24%.2 The skin lesions are characterized by shiny, well-demarcated, erythematous plaques with little scaling.1 Interestingly, inverse psoriasis has been found more commonly in obese individuals and is associated with increased risk for psoriatic arthritis or nail involvement1,3; in addition, intertriginous psoriasis occurs in infants and young children, with 4% suffering from localized psoriatic diaper rash.4 Erythema is also increased in inverse psoriasis due to inflammation and secondary changes from friction, perspiration, and maceration. Stemming from these secondary changes, inverse psoriasis can be diagnostically challenging when also considering candidal intertrigo, tinea infection, irritant, or allergic contact dermatitis. Although overlap exists between inverse and genital psoriasis, inverse psoriasis is a distinct entity with a similar high burden of disease; in fact, 38% of patients with genital psoriasis did not have flexural skin involvement, characteristic of inverse psoriasis.5 With respect to genital psoriasis, reported symptoms include itch (86%), pain (44%), burning (49%), dyspareunia (45%), and worsening lesions after intercourse (34%); these symptoms lead to impairments in sexual function and frequency accompanied by fear of sexual relations.6 In one study, 45.8% of patients did not discuss their genital psoriasis with their physician, indicating low awareness of this condition among physicians.7 In comparison, the impact of inverse psoriasis has been analyzed with the Inverse Psoriasis Burden of Disease tool; this scoring system identified notable symptoms including negative body image, pain, ssuring, skin maceration, and embarrassment.8 The tool also demonstrates the greatest impairments in daily activities such as clothing choice and toileting or personal hygiene.8 Historically, the primary treatment for inverse psoriasis included low-potency topical steroids.9 However, there is concern about side effects including atrophy, ulceration, striae, and telangiectasia especially in areas with little epidermal hyperplasia. Therefore, there is an advantage to topical nonsteroidal, systemic, or phototherapy for extensive disease resistant to topicals. New studies have attempted to demonstrate the efficacy of these treatments. This report will summarize these findings while providing an updated consensus on inverse psoriasis therapy.
