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Chapter 9: Infections of the skin and soft tissue 401

occurs at the site of the primary infection and in ad- the rash. Erythema and crops of vesicles then develop in
jacent areas. Hours or days later vesicles reappear. the same dermatomal distribution. Additional discrete
non-dermatomal lesions are also commonly found. The
Complications vesiclesbecomepustularandthenformcrusts.Theyheal
Patients with atopic eczema may develop eczema her- over 2–3 weeks leaving scars.
peticum (see page 385). Disseminated herpes may occur
in the newborn or immunosuppressed. HSV is the most Complications
common cause of recurrent erythema multiforme. Corneal ulcers and corneal scarring may result from
trigeminal infection with ocular involvement. Dissem-
Management ination is seen in immunosuppressed individuals. Pos-
Aciclovir is of value if used early enough. Topical treat- therpetic neuralgia is found in 5–10% of patients pre-
ment at the onset of tingling may prevent a recur- senting as a continued burning pain.
rence. As aciclovir works to prevent reactivation it is of
limited value in established disease. However, immuno- Investigations
suppressed patients should be treated aggressively with The virus can be isolated from vesicular fluid and iden-
parenteral aciclovir to prevent dissemination. tified on electron microscopy.

Herpes zoster (shingles) Management
Adequate analgesia is essential. Aciclovir is effective in
Definition shortening the duration of pain when started within
Herpes zoster or shingles is an acute self-limiting der- 48 hours of the onset of the rash. It should be given
matomal vesicular eruption occurring in a dermatomal parenterally in the immunocompromised.
distribution.
Human papillomavirus (viral warts)
Incidence
Affects 10–20% of the population at some time in their Definition
lives. Human papillomavirus (HPV) infections affecting ep-
ithelial tissues and mucous membranes.
Age
Incidence increases progressively with age. Aetiology
Human papillomaviruses are double-stranded DNA
Sex viruses. Over 70 subtypes are identifiable and different
M = F subtypes cause infections at different sites of the body:
HPV type 2 causes hand warts, type 1 and 2 cause plan-
Aetiology/pathophysiology tar warts, and various subtypes cause genital warts and
Primary infection with the varicella-zoster virus (VZV) anogenital intraepithelial neoplasia. HPV types 16–18
causes chickenpox. Like other herpes virus infections, it are high-risk subtypes for neoplasia and are associated
then remains as a latent infection in the sensory dorsal with cervical and oral cancer. The virus is spread direct
root ganglia. It is thought that gradual loss of immunity by direct contact, anogenital warts, and HPV infection
underliesreactivationexplainingtheincreasedincidence of the cervix may be sexually transmitted.
with age and the association with immunocompromise
including HIV. Clinical features
1 Common warts are well-demarcated dome shaped
Clinical features papules or nodules with an irregular papilliferous sur-
Pain,tendernessorparaesthesiadevelopsinthedistribu- face. Commonly occur on the back of hands, between
tion of a single dermatome 3–5 days prior to the onset of fingers and around the nail edge.