Genital psoriasis under-identified, has significant impact on patient QoL

Genital involvement in psoriasis is more common than many physicians believe, and it can have a profound impact on patient quality of life— even greater than with face and hand involvement, said Dr. Lyn Guenther, speaking at Dermatology Update in Vancouver in October.

Results from various questionnaires suggest the prevalence of genital psoriasis ranges from 29% to 46%, said Dr. Guenther, professor of dermatology at western University in London, Ont., and past president of the canadian society for Dermatologic surgery. however, she said that if a practitioner asks a psoriasis patient if they have genital involvement, the patient will often say they do not, even if on visual examination they have “a napkin worth of psoriasis” in their genital area.

Mistaken for VD, fungal infection

“Many patients think they have a venereal disease,” she said. "I think this is part of the reason they do not want to bring it to [a physician’s] attention."

Other health care practitioners who encounter the patient may misdiagnose genital psoriasis as a fungal infection and start the patient on anti-fungal therapy, Dr. Guenther said. That may be in part because of the atypical appearance of psoriasis in the genital area. “Often we do not see a large amount of scale because of the maceration of the area. But it is usually bright red.”

Risk factors for genital involvement in psoriasis include inverse psoriasis—as many as 80% of psoriasis patients with inverse psoriasis will have genital involvement, Dr. Guenther said—and male gender, scalp involvement, and nail involvement are also risks. 

QoL impact as severe as facial Pso 

While dermatologists typically talk about psoriasis sited in visible areas, such as the hands and face, having the most impact on patient quality of life, Dr. Guenther said there are studies that show genital psoriasis can result in even more significant impairment of quality of life. 

“[Genital psoriasis] has a large impact on sexual health,” she said. not only are the lesions aesthetically unappealing, “[the lesions] can also be associated with burning when [a patient] has intercourse, [as well as] redness and bleeding.” additionally, in one-third of patients, intercourse aggravates their psoriasis, and that aggravation is another factor that discourages sexual contact. 

Treatment challenges

There is little existing data on how to treat psoriasis in the genital area, noted Dr. Guenther. “There have been a few open-label trials of topical therapies. There have been some algorithms that have come up. There are some scattered case reports,” she said.

“The skin is also very sensitive [in the genital area], more apt to have adverse effects,” she said.

Tazarotene and ultraviolet (UV) light should be avoided in the genital area, partly due to the risk of irritation, and partly because the logistical challenges of exposing the area to the UV source, she said.

The first-line therapy recommended by the few algorithms that have been developed is typically topical corticosteroids. “we will generally start with the weaker ones and then go to stronger ones for short periods of time,” she said. however, Dr. Guenther said in her own practice she has seen skin thinning and striae from topical steroids used in the genital area, which suggests use of stronger steroids should be minimized. 

“Often the weaker steroids, though, just do not [resolve the psoriasis],” she said. Topical calcineurin inhibitors are her first-line therapies, particulary if there is a reason not to use steroids in a particular patient.

She cited an open-label study (J Cutan Med Surg, sept./Oct. 2008; 12(5):230–234), in which 12 male patients with genital psoriasis were treated with topical tacrolimus 0.1% ointment twice daily for eight weeks, followed by four-weeks of observation.

In that study the mean genital PASI scores decreased to 1.2 at week eight from 15.8 at baseline (p<0.001).

If local treatments do not work, or the genital psoriasis is more severe or recalcitrant, treatment can be modified to include systemic agents, she said. 

There has been a clinical trial of ixekizumab for genital psoriasis in which Dr. Guenther participated. The findings were presented at the sexual Medicine society of north america’s Fall 2017 scientific Meeting (abstracts 012, 203, and 204).

Because the presentation of genital psoriasis frequently has less scaling, a new grading system was developed for evaluating genital involvement in this trial, Dr. Guenther said. approximately 40% of the 149 participants had less than 10% body surface area (Bsa) involvement, but all participants were graded as having moderate to severe psoriasis based in part on genital involvement. Genital areas evaluated included the labia minora, labia majora, and the perineum in female participants, and the penis, scrotum, and perineum in male participants.

Improvements seen early

Of the patients in the active 80 mg ixekizumab group, significant improvements vs. placebo were seen as early as week one, and by week 12, 73% of the active-arm patients had achieved clear or almost clear skin vs. 8% in the placebo arm.

“At two weeks there was improvement in genital itching [in the active arm],” said Dr. Guenther. it was also noted that there was also significant improvment in sexual function, she added.

Dr. Guenther said that she hoped dermatologists would not just ask patients if they have genital psoriasis, but check the area to be sure and if psoriasis is present, reassure them that it is common and offer them treatment, “Because [treatment] can have a major impact on their quality of life.”

Non-proprietary and brand names of therapies: tazarotene (Tazorac, Allergan); tacrolimus 0.1% (Protopic, LEO Pharma); ixekizumab (Taltz, Lilly).
 

Originally published in The Chronicle of Skin & Allergy (December 2017; 23(8):page 1,21)