A retrospective study conducted at Amsterdam University Medical Centers identified allergic contact dermatitis as a potential contributor to chronic vulvar symptoms in a high percentage of patients. Among 67 women tested between 2015 and 2024, 86.6% had at least one positive reaction, and 37.9% had a clinically relevant allergy that may have contributed to their symptoms.
Allergens Beyond the Obvious
The most commonly identified allergens were metals, particularly nickel (50.8%), but these were rarely clinically relevant—only one patient’s vulvar symptoms improved after she stopped using a leather bicycle saddle.
Spices and herbs were the second most common allergen group, with 43.3% of patients testing positive. Of those, 34.5% had clinically relevant reactions, and some reported symptom relief after avoiding the offending substances. However, complete avoidance proved difficult. The most common sensitizers were bell pepper, sage, nutmeg, and curry.
Importantly, researchers noted that sensitization may occur not only via direct contact but also through systemic exposure—with allergenic compounds in foods excreted in urine or feces and potentially irritating vulvar skin.
Other Culprits: Fragrances and Preservatives
Fragrance allergens triggered positive reactions in 37.3% of patients, 60% of which were clinically relevant—the highest relevance rate among allergen groups. Patients reported improvements after avoiding perfumed products, such as depilatory wax and dyed underwear. Preservative reactions were also common (29.9%) and clinically relevant in 35% of cases.
A diagnostic clue emerged: patients who reacted to Fragrance Mix 1 were significantly more likely to also react to spices and herbs (P = .002), suggesting this mix may serve as a useful marker when extended spice testing is unavailable.
Patient Profiles and Delayed Diagnoses
Participants had long-standing symptoms, with a median duration of 36 months and a mean of 72 months before patch testing was performed. Nearly half (49.4%) had an atopic background (e.g., eczema, asthma), which may have predisposed them to allergic contact dermatitis (ACD) by compromising the skin barrier.
Clinical Takeaway
“Both topically applied cosmetic and medicinal products, as well as systemically ingested substances, such as spices and herbs, may contribute to ACD affecting the vulvar region. To enhance diagnostic accuracy, patch test series should be tailored to the patient's clinical history and specific allergen exposures.” —Blom et al., Contact Dermatitis, 2025
The authors recommend initiating patch testing with the European Baseline Series and selecting additional series—such as spices and herbs—based on the patient’s individual exposure history. They emphasize the importance of early testing to avoid long diagnostic delays and improve outcomes in women with persistent vulvar complaints.
The authors declared having no competing interests.
Source: Contact Dermatitis
