A 27-year-old woman presents to her primary care physician for an abnormal vaginal discharge. The patient has engaged in unprotected intercourse with 12 different partners. She has a medical history of asthma, IV drug abuse, and depression. She has 1 to 2 alcoholic drinks per day. She feels ashamed of her behavior and is requesting treatment for her condition and advice for safe sex. The patient is given antibiotics and is advised on safe sex practices. The patient presents to the emergency department 3 days later with a complaint of a rash. She states that every time she has sex a rash has emerged on her skin. Her temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 91/min, respirations are 14/min, and oxygen saturation is 98% on room air. A physical exam is notable for the finding in Figure A. Which of the following is the most likely cause of this patient's symptoms?
Photosensitivity
Antigen exposure
IV drug use
Infection
Antigen exposure
This patient is presenting with urticaria whenever she engages in sexual intercourse suggesting a latex allergy (found in condoms). These allergies are due to antigen exposure.

Anaphylaxis and urticaria are immunologically mediated responses to environmental antigens that are typically IgE-mediated. This results in crosslinking of antigen receptors and the subsequent release of histamine and other inflammatory signals. Patients can present with a spectrum of symptoms from urticaria (hives alone) all the way to full-blown anaphylaxis (hypotension, tachycardia, and bronchoconstriction). Minor cases can be treated with avoidance of antigen exposure. Anaphylaxis is treated with intramuscular epinephrine (1:1,000).

Gawchik reviewed the evidence regarding the diagnosis of latex allergy. She discusses how the diagnosis is primarily made by observing the relationship between exposure and symptoms. She recommends avoidance of latex in these patients.

Figure/Illustration A is a clinical photograph that demonstrates dermal edema and urticaria (red circles). This can occur secondary to allergen exposure such as from a new drug or latex.

Incorrect Answers:
Answer B: Drug reaction could be possible if this patient has an antibiotic allergy (ceftriaxone is a treatment for gonorrhea); however, a rash that only occurs during intercourse is more likely related to latex exposure.

Answer C: Infection is possible given this patient’s IV drug abuse and risky behavior; however, the hives present in this patient are likely not related to an infection. Infectious rashes tend to be painful, ulcerative, or vesicular.

Answer D: IV drug use could expose this patient to any number of foreign substances that could induce an allergic reaction; however, the symptoms that are associated with sexual intercourse point toward latex exposure.

Answer E: Photosensitivity would not present as hives but could occur in this patient given that doxycycline is an appropriate drug to treat her initial sexually transmitted infection and offers coverage for Chlamydia trachomatis. Patients would present with a photosensitive rash.

Bullet Summary:
Anaphylaxis and urticaria can occur secondary to latex exposure (such as from condoms or gloves).