Herpes Simplex Infection of the Skin

Essentials

• In addition to oral and genital mucosa, a Herpes simplex infection may also occur on the skin.
• The diagnosis is usually based on the clinical picture and recurrence of symptoms in the same place.
• A periocular herpes infection requires emergency consultation of an ophthalmologist.
• Antiviral medication can be used to alleviate the symptoms and shorten the duration of the disease but it will not eradicate the virus.
• Prophylactic medication can be used for frequently recurring herpes infections.

Aetiology

• Both Herpes simplex viruses (HSV-1 and HSV-2) cause skin infections. HSV-1 is more commonly involved in skin infections, HSV-2 in infections in the genital area.
• The primary HSV-1 infection is often asymptomatic or causes only few symptoms, and/or is not recognized as a herpes infection. HSV-2 infection usually occurs in adulthood.
• In some people, the primary infection may cause severe symptoms (e.g. gingivostomatitis, pharyngitis, genital herpes).
• Primary skin infections are also possible but rare.
• The virus remains latent in the nervous system and may be activated from time to time, often triggered by environmental factors.

Prevalence

• Herpes virus carriership is very common in the adult population: 40-50% and 15-20% for HSV-1 and HSV-2, respectively. Most carriers never have symptoms.

Symptoms

• The symptoms and the clinical picture are often typical, and the diagnosis is usually based on the clinical picture.
• Before the occurrence of skin lesions, there is usually pain, burning and tingling in the area involved.
• Patchy, clearly defined erythema can be seen at first and, later, groups of vesicles containing clear fluid.
• Individual vesicles may merge and become pustular or haemorrhagic.
• Groups of vesicles may occur on nearby skin areas. After their eruption, small polycyclic erosions usually remain on the surface of the skin.
• The disease usually continues for 1 to 2 weeks but it may last longer in some patients.
• The typical skin areas are the perioral area Viral Infections of the Oral Mucosa (pictures 1 2), face (picture 3), genital area Genital Herpes (pictures 4 5), buttocks, perianal area, hands and fingers (pictures 6 7) http://www.dynamed.com/condition/herpetic-whitlow#SKIN.
• Herpes on the skin usually represents reactivation of latent infection.
• Factors that may trigger reactivation include common cold, or flu, mechanical trauma, medical or dental procedures, injury, stress, UV exposure, sunburn, periods, secondary infection through fingers from, for instance, the lips or genital area (autoinoculation).
• Widespread infection (disseminated disease) can be seen in people with immune deficiency (e.g. HIV infection) and/or immunosuppressive medication (e.g. antirheumatic medication, cytotoxic drugs) Infections in Immunosuppressed and Cancer Patients.
• In patients with atopic eczema, the infection may be widespread particularly on the face (eczema herpeticum; picture 8). This does not represent immunodeficiency.

Differential diagnosis

• Differential diagnostic alternatives are presented in table T1.

Workup

• In a typical case, no examinations are needed, the clinical picture providing sufficient information.
• The virus can be shown by nucleic acid detection or by culture http://www.dynamed.com/lab-monograph/herpes-simplex-virus-culture#SUSPECTED_GENITAL_HERPES_SIMPLEX.
• A culture specimen can best be taken by piercing a vesicle and rubbing the erosive surface with a cotton swab.
• Antibody tests may show carriership but not the time or site of infection. Antibody levels are generally not elevated in disease restricted to the skin (reactivation) but in primary infection they become slowly elevated. Determining antibody levels in herpes infections of the skin is of no use.
• Nucleic acid detection (in cerebrospinal fluid) http://www.dynamed.com/lab-monograph/herpes-simplex-virus-dna-assay#SUSPECTED_HERPES_SIMPLEX_ENCEPHALITIS and antibody detection, as necessary, are used to diagnose central nervous HSV infections and neonatal herpes.
• In unclear cases, or if no response can be obtained by empirical treatment, bacterial and/or fungal samples can be taken from the area of the lesions.
• Allergic contact dermatitis is diagnosed by epicutaneous tests.
• If the clinical picture is severe and response to treatment poor, the possibility of immunodeficiency should be kept in mind (e.g. HIV, haematological malignancies, other malignant diseases) Infections in Immunosuppressed and Cancer Patients.

Treatment

• Very restricted herpes infections do not necessarily require pharmacological treatment.
• Antiviral medication has been found effective in the treatment of herpes infections of the skin http://www.dynamed.com/condition/herpetic-whitlow#MEDICATIONS, mucosa http://www.dynamed.com/condition/oral-herpes#ANTIVIRALMEDS and genital area http://www.dynamed.com/condition/genital-herpes#FIRST_CLINICAL_EPISODE.
• The sooner the treatment is started, the more effective it is.
• The patient should learn to recognize the first symptoms of the disease and to start medication independently.
• In immunosuppressed patients Aciclovir and Valaciclovir in the Prevention and Treatment of Herpes Simplex Virus in Patients Being Treated for Cancer systemic treatment (oral or intravenous depending on the clinical picture) should be started quickly, even if the symptoms are mild or if herpes infection is only suspected, to avoid spread of the infection and/or progression to a necrotizing infection.
• Systemic medication (table T2)
  • The period of treatment is 5 days; in patients with severe symptoms, it may be necessary to extend the treatment to 7 to 10 days.
  • In patients with immune deficiency, higher doses are recommended (e.g. valaciclovir 2 × 500 mg twice daily).

• Topical treatment
  • There is no strong evidence of efficacy in herpes infections of the skin but in mild cases it may be sufficient.
  • Antiviral drugs: aciclovir or penciclovir cream every 2 to 4 hours during the daytime in courses of 5 to 10 days
  • In the blister phase, moist compresses drying the skin, for instance, for 15 minutes 2 to 3 times daily, followed by zinc paste or lotion
  • In some patients, analgesics may be necessary.

Specialist consultation

• In patients with immune deficiency, if there is even a mild herpes infection or clinical suspicion of such an infection, systemic treatment should be started quickly in primary health care, already.
• Patients with severe, widespread clinical disease, particularly those with immune deficiency (patients with cancer Aciclovir and Valaciclovir in the Prevention and Treatment of Herpes Simplex Virus in Patients Being Treated for Cancer, patients on immunosuppressive medication) usually need parenteral aciclovir, most often as emergency treatment at a hospital. Specialized services should be consulted Infections in Immunosuppressed and Cancer Patients.
• A herpes infection close to the eyes (picture 16) with even minor irritation of the eye is an indication for emergency consultation of an ophthalmologist.