Genital Psoriasis or Thrush: How to Differentiate Them?

Intimate fungal infection is a benign genital condition, secondary to a microscopic yeast-type fungus. In the majority of cases, it is caused by the Candida Albicans, naturally present in the genital apparatus. This type of yeast thrives in an acidic aerobic environment, which explains why it multiplies in mucous membranes, skin folds, on nails or in hair. In the case of candidiasis, these microorganisms develop in the mucous membranes and proliferate rapidly.

In women, vaginal yeast infection presents itself through several indicative signs:

• Thick white discharges ;

• Persistent itching at the entrance of the vagina and the vulva;

• Experiencing vaginal burns during urination;

• A swollen vulva, of a bright red colour;

• Painful sexual intercourse.

In humans, this condition manifests as an inflammation of the foreskin and glans, accompanied by itching. Without appropriate treatment, it can progress to a purulent discharge or phimosis.

Intimate fungal infections can also result from a natural imbalance in the vaginal flora, and in this case, may heal on their own. However, it is important to monitor factors that promote the proliferation of the fungus, among others:

• The wearing of tight and/or synthetic fabric underwear;

• The use of harsh intimate care products;

• The use of contraceptive pills or antibiotics;

• Stress;

• Excessive intimate hygiene;

Unlike the lesions caused by psoriasis in its classic form, genital psoriasis can present in several ways, which can lead to confusion with other genital diseases, notably thrush. Indeed, as mentioned earlier, several factors can lead to irritation of the intimate areas. Hence, the need for an accurate diagnosis. Clinical manifestations also include red plaques with regular borders around the intimate parts.

In most instances, genital psoriasis results in burning sensations, itching, and even pain. Furthermore, a clinical study has gathered the experiences of individuals affected by genital psoriasis. According to their findings, they have less frequent sexual intercourse, a reduced sexual desire, and they avoid sexual relations. Additionally, they may experience certain discomfort during intercourse.

In essence, several characteristics distinguish genital psoriasis from fungal infection:

• The primary cause of the disease:

  Genital psoriasis is an autoimmune disease linked to an immune system failure, leading to an excessive proliferation of keratinocytes and a genetic predisposition. Genital or vaginal yeast infection, on the other hand, is secondary to a fungus, the Candida Albicans.

• In terms of clinical signs:

  Genital fungal infections typically cause redness, itching, and burning. Heavy vaginal discharge is a distinctive symptom of yeast infection in women. In men, this condition leads to inflammation, whereas psoriasis only causes irritations, in the form of red patches.

• Identification of affected areas.

  Genital psoriasis plaques are specifically located in the genital region, including the pubis, external genital organs, and the groin. Genital fungal infections typically affect the genital parts, but can also spread to other surrounding areas, such as the groin, mucous membranes, and skin folds.

• The diagnosis.

  The diagnosis of genital psoriasis is primarily clinical, based on the appearance of the lesions and the patient's medical history. Genital fungal infections may sometimes require diagnostic tests, such as smears, to confirm the presence of yeasts. These examinations are not painful and allow the dermatologist to distinguish between these two skin conditions.

• Progression of the condition.

  Genital psoriasis plaques can be persistent and recurrent. They may progress in the form of flare-ups, improving and deteriorating periodically. Yeast infections, on the other hand, tend to develop rapidly and can cause intense symptoms, but they generally resolve quickly with appropriate treatment.

• The treatments.

  The treatment of genital psoriasis may involve the use of topical creams containing dermocorticoids, immunosuppressants, and other medications prescribed by a dermatologist. Yeast infections can generally be treated with topical or oral antifungals, available over-the-counter or by prescription.

MEEUWIS K. A. P. & al. Genital Psoriasis: A Systematic Literature Review on this Hidden Skin Disease. Acta Dermato-Venereologica (2011).

DURAND B. Traitements des mycoses vulvo-vaginales aiguës et récidivantes. Sciences pharmaceutiques (2017).

YANG E. J. & al. The impact of genital psoriasis on quality of life: a systematic review. Psoriasis: Targets and Therapy (2022).