A rare medical case in Lithuania reveals a possible link between an unusual sensitivity to semen and fertility difficulties in a 29-year-old woman, following a long and complicated diagnostic journey.
The story began with a 29-year-old Lithuanian woman struggling to conceive despite repeated attempts with her partner, including two unsuccessful IVF cycles. Gynecological examinations revealed no clear cause for infertility, and it was not mentioned whether her partner had undergone fertility testing.
At the same time, the woman was suffering from asthma and allergies to airborne substances such as dust, mold, and animal dander, which prompted her to visit a specialized medical center to find out if these allergies were affecting her chances of having children.
During the examinations, blood tests showed an abnormally high level of eosinophils, immune cells associated with allergies. Skin tests also revealed allergies to dust mites, grass pollen, and animal and insect allergens, in addition to her known allergy to dogs.
Doctors investigated the case further after discovering a severe allergy to a protein called Canis familiaris allergen 5, found in dogs. They explained that this protein may be structurally similar to some proteins found in human semen, raising the possibility of an allergic reaction upon exposure.
Indeed, the patient reported experiencing symptoms such as sneezing and nasal congestion after unprotected sexual intercourse, symptoms that had not been previously explained in the fertility assessments she had undergone.
To confirm the diagnosis, doctors performed a test using her partner's semen sample. The results showed an allergic reaction, confirming her allergy to human seminal plasma, the fluid component that carries sperm. Doctors believe this type of allergy can lead to inflammation in the reproductive system and may be a contributing factor in some cases of female infertility.
As for treatment, the most common option was using condoms to avoid exposure to the allergen, but the patient refused because she wanted to become pregnant. Doctors also mentioned the possibility of treatment by gradually exposing the body to increasing amounts of semen, but this method is not available in Lithuania.
Instead, she was given antihistamines before intercourse, but this did not produce any significant improvement in her condition. During a three-year follow-up, her infertility persisted, and she even developed more severe symptoms such as burning in the genital area, swollen eyelids, and excessive tearing after exposure to semen.
This condition is rare worldwide, with only about 80 cases of seminal plasma allergy documented, and its effects on fertility are still not fully understood, especially when combined with other health factors.
The doctors conclude their report by noting that this case underscores the importance of considering immunological factors more broadly when assessing infertility, even when the causes appear outwardly unrelated.
