Herpes simplex (cutaneous)

What it is

A common viral infection.

• HSV 1 favors the mouth and nose; HSV type 1 gives lip and skin lesions - Upper is 1.
• HSV 2 favors the genitalia, buttocks, thighs; HSV type 2 gives genital lesion - Low is 2.

After the primary infection the virus stays latent. The dendritic ulcer represents a reactivation of a latent virus which is dormant in the trigeminal ganglion.

How it presents

Painful, grouped vesicles on an erythematous base; the vesicles go on to ulceration.

• HSV-1: herpetic gingivostomatitis, and herpes labialis with cold sores and fever blisters.
• HSV-2: genital herpes, clusters of genital sores consisting of inflamed papules and vesicles. Can lead to dysuria, urinary retention (involvement of spinal cord), cervicitis and proctitis.

The derm case: a 22 years old female presented with painful rash over her lips; the skin findings are multiple grouped vesicles over lateral side of the lower lip; the diagnosis is herpes simplex.

Where the eye is involved, the history is of a past primary infection such as perioral vesicles and a recent immunosuppression or illness.