Why would an allergic reaction cause localized itching and swelling in the vagina?

Why Allergic Reactions Can Cause Localized Itching and Swelling in the Vagina

Localized vulvar and vaginal itching and swelling can occur as isolated symptoms of seminal plasma hypersensitivity without progressing to systemic anaphylaxis. 1

Mechanisms of Localized Allergic Reactions

• Allergic reactions in the vaginal area can be localized due to direct contact between the allergen and the vaginal mucosa, which has the ability to respond to allergenic stimuli 2
• The vaginal mucosa contains mast cells that release inflammatory mediators when exposed to allergens, causing localized symptoms without systemic involvement 1
• Seminal plasma proteins with molecular weights ranging from 12 to 75 kd can trigger IgE-mediated localized reactions in the vagina 1
• Localized vulvar and vaginal burning, itching, and swelling may occur as isolated symptoms after ejaculation without progression to systemic symptoms 1

Types of Vaginal Allergic Reactions

• Direct exposure to allergens (contact with vaginal mucosa):

  • Human Seminal Plasma is the most prevalent direct allergen, sensitizing 73% of affected women 2
  • Localized swelling and burning are the most common symptoms in these cases 2
  • These reactions begin within seconds to minutes after ejaculation 1

• Indirect exposure or unidentified allergens:

  • House dust mites (54%) and pollen (44%) can cause vulvovaginal allergic responses even without direct contact 2
  • Vulvar pruritus and burning are predominant symptoms in these cases 2

Differential Diagnosis Considerations

• Seminal plasma hypersensitivity is essentially a diagnosis by exclusion 1
• Other causes to rule out include:
  • Sexually transmitted infections 1
  • Latex sensitivity from condoms 1
  • Transfer of food or drug proteins through semen 1
  • Contact dermatitis from hygiene products or fragranced sanitary products 1, 3
  • Vulvovaginal candidiasis, which can cause similar symptoms 1, 4

Clinical Presentation of Localized Reactions

• Localized reactions typically present with:

  • Vulvar and vaginal itching 1, 2
  • Localized swelling 1
  • Burning sensation 1, 2
  • These symptoms may occur without any systemic manifestations 1

• In contrast, systemic seminal plasma protein anaphylaxis presents with:

  • Diffuse pruritus and urticaria 1
  • Pelvic pain associated with uterine contractions 1
  • Nasal symptoms (rhinorrhea, sneezing) 1
  • Respiratory symptoms (wheezing, dyspnea, laryngeal edema) 1
  • Rarely, hypotension and syncope 1

Important Clinical Considerations

• There is no evidence to support that localized vaginal seminal plasma hypersensitivity increases susceptibility to future systemic anaphylactic symptoms 1
• Localized and/or systemic seminal plasma hypersensitivity is not associated with infertility 1
• Prevention of reactions can be accomplished by correct use of condoms 1
• For treatment of localized symptoms, topical hydrocortisone may temporarily relieve itching associated with minor skin irritations and inflammation 5

Diagnostic Approach

• Skin prick testing with whole human seminal plasma from the male partner is recommended for initial screening 1, 2
• In vitro tests (RAST and ELISA) of serum specific IgE are less sensitive than skin testing 1
• A negative serologic test result for seminal plasma specific IgE does not exclude sensitization 1
• Patch testing may be useful to identify other potential allergens causing contact dermatitis of the vulva 3, 6