Herpes simplex is a common viral infection that affects most people at some point in their lives. It presents with localised blistering that is often referred to as cold sores.
Type 1 HSV is mainly associated with oral and facial infections, while type 2 HSV is more commonly associated with genital and rectal infections. However, either can affect almost any area of skin or mucous membrane.
Primary attacks of HSV are common in infants and young children, especially where there is close contact or over-crowding. It is spread via direct or indirect contact with an infected person. Primary infection may be (almost) asymptomatic but can include high fever and feeling unwell. In small children with gingivostomatitis associated with type 1 HSV achieving adequate oral intake can be a problem as eating and drinking are painful.
Neonatal herpes is a rare but serious condition that can lead to systemic infection and CNS disease, with a mortality of around 30%. Clustered red papules and vesicles appear shortly after birth. These become pustular, crusted and haemorrhagic over 2-3 days. The neonate should be admitted for antiviral therapy.
Mild, uncomplicated eruptions do not usually require treatment but more severe infection in unwell patients may require antiviral therapy.
In people with eczema, HSV may result in severe and widespread infection , known as eczema herpeticum. It starts with clusters of itchy, painful blisters with new patches forming and spreading over 7-10 days. Lesions classically have a “punched out” appearance. Patients with eczema herpeticum are systemically unwell with high fever and swollen lymph nodes. Severe infection can affect multiple organs, including the eyes, brain, lungs and liver.
Secondary bacterial infection with staphylococcus or streptococcus can lead to impetigo and cellulitis.
Eczema herpeticum is one of the few dermatological emergencies. Antiviral treatment should be given urgently. In children this is usually intravenous, unless infection is very localised and the child is relatively well. Commonly, children are admitted for treatment with aciclovir and antibiotics to manage secondary infection. Lesions around the eyes should prompt ophthalmology assessment.