Erythema Nodosum: A Manifestation of Trichomoniasis and Vulvovaginal Candidiasis

Background: Erythema nodosum (EN) is the most common form of septal panniculitis resulting from a hypersensitivity reaction in response to numerous antigens or triggers. Case: A 43-year-old female presented with a chief complaint of erythematous painful non-ulcerating nodules on the lower limbs for 18 months. This was preceded by a painful, erythematous rash consisting of a few subcutaneous nodules on both limbs. A dermatological examination of the tibia region revealed multiple tender erythematous and hyperpigmented nodules. A biopsy and serology test were performed to rule out differential diagnoses. Based on the data, the working diagnosis is erythema nodosum caused by trichomoniasis and vulvovaginal candidiasis. We managed this case with metronidazole 500 mg twice daily for seven days, fluconazole 150 mg as a single dose, and non-steroidal anti-inflammatory drugs. One week after receiving treatment, her pain complaint disappeared, but the hyperpigmented macules still persisted, although they had decreased. One year after treatment, the patient's complaints did not recur. Discussion: EN may be associated with a wide variety of disease processes, and its observation should be followed by finding the underlying etiology. The clinical presentation includes symmetrical, tender, erythematous, warm nodules, and raised plaques usually located on the shins, ankles, and knees. The lesions show spontaneous regression without ulceration, scarring, or atrophy, and recurrent episodes are uncommon. The EN diagnosis is based on clinical presentation and histopathological findings. Conclusion: The management of erythema nodosum involves identifying the etiologic factor and focusing on eliminating exposure or treating the underlying diseases.