What are the key clinical features that help differentiate between oral HSV-1 and genital HSV-2 infections in primary care?

Key clinical features differentiating primary oral HSV-1 infection from primary genital HSV-2 infection in primary care include the anatomical site of lesions, symptom presentation, and systemic involvement.

Primary oral herpes simplex virus type 1 (HSV-1) infection typically presents with painful vesicular lesions on the lips, oral mucosa, and gingiva, often accompanied by gingivostomatitis, which includes swollen, erythematous gums and difficulty eating or swallowing. Systemic symptoms such as fever, malaise, and lymphadenopathy are common in primary oral infection, especially in children and young adults. The lesions usually heal within 2 weeks without scarring ¹.

In contrast, primary genital herpes simplex virus type 2 (HSV-2) infection presents with painful grouped vesicles and ulcers on the genitalia, perineum, or perianal area. These lesions are often associated with dysuria, urethritis, and tender inguinal lymphadenopathy. Systemic symptoms such as fever, headache, and myalgia are also frequent during primary genital infection. The initial episode tends to be more severe and prolonged than recurrent episodes, with lesions healing over 2 to 4 weeks ¹[(Thin, 1991)].

While both infections can cause systemic symptoms and painful vesicular lesions, the key differentiator in primary care is the lesion location: oral mucosa and lips for HSV-1 versus genital and perianal skin for HSV-2. Additionally, primary oral HSV-1 infection often presents with prominent gingivostomatitis, which is not a feature of genital HSV-2 infection. Conversely, genital HSV-2 infection is more likely to cause dysuria and inguinal lymphadenopathy ¹[(Thin, 1991)].

In summary, the clinical distinction relies primarily on lesion location and associated symptoms: oral vesicles with gingivostomatitis and systemic symptoms suggest primary HSV-1, whereas genital vesicles with dysuria and inguinal lymphadenopathy suggest primary HSV-2 infection in a primary care setting ¹[(Thin, 1991)].