Unilateral Presentation of Genital Warts
Yes, it is completely normal for HPV genital warts to present on only one side of the vulva or perianal area, and it is also common for them to be difficult to visualize but easily palpable by the patient. 1
Why Unilateral Presentation is Normal
Genital warts can occur at single or multiple sites in the anogenital epithelium and do not follow a symmetrical distribution pattern. 1 The location and distribution of warts depends on where viral inoculation occurred during sexual contact, which is often asymmetric and focal. 2
HPV types 6 and 11 (which cause 90% of visible genital warts) infect specific areas of contact, including the vulva, perineum, and perianal skin, and there is no biological requirement for bilateral involvement. 1, 3
Warts commonly appear as single or multiple lesions that may be isolated to one anatomic area rather than distributed symmetrically. 4, 5
Why Warts Can Be Difficult to See But Palpable
Diagnosis of genital warts is usually made by visual inspection, but genital warts are often asymptomatic and can be subtle in appearance, making them more easily felt than seen. 1
Genital warts can present in various forms: cauliflower-like, flat, papular, keratotic, or the same color as surrounding skin, with flat and papular variants being particularly difficult to visualize. 4, 5
Depending on size and anatomic location, warts might be pruritic (itchy), which explains why the patient scratches the area and can palpate them more easily than they can be seen. 1
The CDC notes that subclinical "flat" warts can be found on any mucosal or cutaneous surface and may be detected by touch before they are visible. 2
Important Clinical Considerations
Biopsy should be considered if the diagnosis is uncertain, lesions don't respond to standard therapy, the patient is immunocompromised, or the warts are pigmented, indurated, fixed, bleeding, or ulcerated. 1, 6
The application of 3-5% acetic acid (which causes HPV-infected tissue to turn white) is not a specific test for HPV infection and is not recommended for routine screening. 1
HPV DNA testing is not recommended for diagnosis of genital warts, as test results would not alter clinical management. 1, 6
Differential Diagnosis to Consider
While unilateral palpable lesions are consistent with genital warts, other conditions should be considered:
Vestibular papillomatosis (a normal anatomic variant that can mimic warts). 6
Condyloma lata (secondary syphilis, which requires serologic testing). 6
Squamous intraepithelial neoplasia or carcinoma (especially if lesions are atypical, pigmented, indurated, or fixed). 1, 6
Treatment Approach
Treatment should be guided by patient preference, wart size, number, and anatomic location, with no single treatment superior to others. 1
First-line options include cryotherapy with liquid nitrogen, patient-applied podofilox 0.5%, or provider-applied TCA/BCA 80-90%. 6, 4
Most genital warts respond within 3 months of therapy, though recurrence occurs in approximately 30% of cases regardless of treatment method. 1, 6
Genital warts can be left untreated if the patient prefers, as they may resolve spontaneously, remain unchanged, or increase in size or number. 1