Types of Psoriasis – FLEXURAL/INTERTRIGINOUS (INVERSE PSORIASIS) and GENITAL PSORIASIS

blog-20

Inverse psoriasis

 also known as flexural or intertriginous psoriasis is a rare form of psoriasis that occurs in the flexural skin folds. Plaque psoriasis is most commonly found on the trunk and extensor surfaces of the body, such as the knees, elbows, sacral (lower back) area, and scalp whereas Inverse psoriasis is found in the folds of the axilla (armpits), submammary (breast) folds, and groin (inguinal) and buttock folds. It can occur in any area where two skin surfaces meet. The inguinal fold is the most commonly affected area, followed by the axilla and the external genitalia. The skin at the inverse body sites differs from skin at extensor sites with less epidermal keratinization (thinner skin) and more sweat glands. The most evident difference between classical plaque-type psoriasis and inverse psoriasis is the lack of, or less, scaling. The lesions are usually well demarcated, erythematous (red), and are often shiny, appear moist, weepy and fissured. The irritation may be increased in inverse psoriasis as a result of the rubbing and sweating involved in the skin folds. 1, 2   

Approximately 3–7% of psoriasis patients present with inverse psoriasis and patients with palmar psoriasis have a greater chance of having inverse psoriasis as compared with plaque psoriasis. In one study of 170 psoriasis patients with palmar involvement, 5.3 times more patients had inverse psoriasis than patients with plaque psoriasis. Development of inverse psoriasis has been reported as a paradoxical side effect to treatment with infliximab for Crohn’s disease and hidradenitis suppurativa. Inverse psoriasis has been observed to be more common in the obese population possibly due to the rubbing of the skin folds. 1, 2

Inverse psoriasis affecting the genitalia seems to be underreported and undertreated; and approximately 35% patients with genital psoriasis never speak to their physician about their genital lesions. Nearly 70% of Physicians do not offer treatment for genital lesions. 3

Flexural Psoriasis 3

A study on the quality of life and sexual life in 487 patients with genital psoriasis concluded that3:

  • patients with genital lesions report even significantly worse quality of life than patients without genital lesions;
  • sexual distress and dysfunction are particularly prominent in women;
  • sexual distress is especially high when genital skin is affected;
  • the attention given to possible sexual problems in the psoriasis population by healthcare professionals is perceived as insufficient by patients.     

Flexural Psoriasis 2

Results of several questionnaire-based surveys show that involvement of the genital skin region occurs in 29–40% of patients with psoriasis. The genital area may frequently be involved in cases of inverse psoriasis. Of 48 patients with inverse psoriasis, the external genitalia were involved in 38 (79.2%). 4

Flexural Psoriasis 1

In another report researchers stated that patients with genital psoriasis have significantly worse quality of life (QoL) scores compared with patients without genital lesions. In addition, numerous patients with psoriasis have sexual dysfunction. Between 25–40% of patients reported a decline of sexual activity since the onset of psoriasis, mainly due to diminished sexual desire, embarrassment of physical appearance and inconvenience caused by scaliness of the skin or topical therapy. Particularly in women with genital psoriasis, sexual distress is higher and sexual function is more significantly impaired compared to those without genital lesions. 4

Inverse psoriasis is often misdiagnosed for bacterial or fungal intertrigo. Intertrigo is inflammation of opposed skin folds caused by skin-on-skin friction that presents as erythematous, macerated (moist, broken, soft skin) plaques. Secondary bacterial and fungal infections are common because the moist, denuded skin provides an ideal environment for growth of microorganisms. Candida is the most common fungal organism associated with intertrigo. Intertriginous candidiasis also presents as well demarcated, erythematous patches but with tell tale satellite papules or pustules at the periphery (around the edges). Candida, Staphylococcus aureus and Malassezia furfur have been shown to colonize psoriatic skin lesions so diagnosis for flexural psoriasis is sometimes not easy. Candida species have been isolated from the skin of 15% of psoriasis patients compared to only 4% in the control group. 5, 6 However, some studies have also suggested that Candida is not commonly found in psoriatic lesions of inverse of genital psoriasis.

Application of topical treatment in the intertriginous areas is considered as treatment under occlusion due to enhanced hydration and increased skin absorption. However, the inverse areas are considered more sensitive and prone to side effects from topical steroids (i.e. due to thinner skin at these locations). 2

 

REFERENCES

  1. Syed Z. U. and Khachemoune A.; Inverse Psoriasis Case Presentation and Review; Am J Clin Dermatol 2011; 12 (2): 1-4 1175-0561/11/0002-0001/$49.95/0
  2. Silje Haukali Omland  and Robert Gniadecki; Psoriasis inversa: A separate identity or a variant of psoriasis vulgaris?; Clinics in Dermatology (2015) 33, 456–461
  3. Meeuwi  K.A.P. et al.; Genital Psoriasis: A Systematic Literature Review on this Hidden Skin Disease;  Acta Derm Venereol 2011; 91: 5–11
  4. Meeuwis KAP, et al.; Genital Psoriasis Awareness Program: Physical and Psychological Care for Patients with Genital Psoriasis. Acta Derm Venereol. 2015, 95, 211–216
  5. Wilmer E.N. et al.; Resistant “Candidal Intertrigo” ”: Could Inverse Psoriasis Be the True Culprit?; doi: 10.3122/jabfm.2013.02.120210
  6. Taheri Sarvtin, et al.;. Evaluation of candidal colonization and specific humoral responses against Candida albicans in patients with psoriasis. International Journal of Dermatology. Dec2014,Vol.53Issue12, pe555-e560. 6p.

TYPES OF PSORIASIS – PLAQUE PSORIASIS

blog-24

Plaque psoriasis or Psoriasis vulgaris (common type) – affects between 58% and 97% of all psoriasis cases. The difference in prevalence can be explained by race and geographical placement.1

It is characterized by sharply demarcated erythematous (red), silvery (whitish/yellowish), scaling plaques which most commonly occur on the elbows, knees, scalp, chest, back, and groin regions. The lesions are well-defined round or oval plaques that differ in size and in chronic plaque psoriasis often coalesce to form very large lesions covering large areas of the body.  Other involved areas include the ears, glans penis, perianal region, and sites of repeated trauma.

The lesions vary in size from 0.5 cm in diameter to large confluent areas on the trunk and limbs. There is a sharp line of demarcation between a plaque and clinically normal, uninvolved skin. Longitudinal studies of individual plaques have demonstrated that plaques are dynamic with an active and expanding edge, sometimes to the extent that the advancing edge may become annular leaving clinically normal skin in the centre of the original plaque.2,3

Plaque psoriasis can present in several different ways.

plaque-psoriasis

Figure 1. Plaque Psoriasis – colour varies from pinkish red to deep red, shiny with minimal silvery scale. Multiple lesions often coalesce forming larger plaques. This patient would be classified has having sever psoriasis

rupioid-sub-type

Figure 2. Plaque Psoriasis –  Rupioid subtype  Deep violaceous annular (round) lesions with distinctive, thickened, silvery scale. Multiple small lesions can be seen to be coalescing.

The term rupioid relates to distinct morphological subtype of plaque psoriasis. Rupioid plaques are small (2–5 cm in diameter) and highly hyperkeratotic, resembling limpet shells (see Figure 2).

A white blanching ring, known as Woronoff’s ring, may be observed in the skin surrounding a psoriatic plaque.

Other morphological subtypes of plaque psoriasis:-

  • Psoriasis gyrate — Figure 3 – in which curved linear patterns predominate annular psoriasis (psoriasis annularis – see figure 7 & 8) )—in which ring-like lesions develop secondary to central clearing

gyrate-sub-type Figure 3

  • Psoriasis follicularis — Figure 4 – in which minute scaly papules are present at the openings of pilosebaceous (hair) follicles.

Psoriasis - Folicularis Figure 4

  • Ostraceous psoriasis (see Figures 5 & 6 below) refers to hyperkeratotic plaques –  extremely thick scaled plaques often resembling an oyster shell.

ostraceous-fig-6 Figure 5                ostraceous-fig-5 Figure 6

Plaque psoriasis (see Figures 7 & 8 below) with a discoid (circular or oval) appearance is called psoriasis annularis or annular psoriasis.

psoriasis-annularis-fig-8 Figure 7                  Psoriasis - Annularis Figure 8 

Scale is typically present in plaque psoriasis, is characteristically silvery white, but may appear a yellowish colour and can vary in thickness.

Removal of scale may reveal tiny bleeding points (Auspitz sign – See Figure 9). The amount of scaling varies among patients and even at different sites on a given patient. In acute inflammatory or exanthematic psoriasis, scaling can be minimal and erythema may be the predominant clinical sign.4

OLYMPUS DIGITAL CAMERA
Figure 9. Thickened, red lesions with fine silvery scale. Multiple lesions have coalesced to form a large plaque. Note the excoriations marks where the patient has scratched the surface of the plaque to reveal pinpoint capillary bleeding, known as Auspitz sign
  • Lichenified psoriasis (Figure 10 and 11) – thickened psoriasis caused by chronic scratching (eczematized)

lichenified-2 Figure 10        lichenified Figure 11

Elephantine psoriasis (Figure 12 and 13) – large persistent, leathery plaques 

Psoriasis - Elephantine 1  Figure 12                Psoriasis - Elephantine Figure 13

Presentation examples of Plaque Psoriasis

Plaque Psoriasis 11 plaque-psoriasis-10  Plaque Psoriasis 9

plaque-psoriasis-8 plaque-psoriasis-7 plaque-psoriasis-6 plaque-psoriasis-5

Plaque Psoriasis 4 plaque-psoriasis-3  plaque-psoriasis-2 plaque-psoriasis-1

Read also “Psoriasis – Severity and Types”