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Skin and soft tissue infectionsViral infections

Skin and soft tissue infectionsViral infections

Eczema herpeticum

This is defined as dermatitis with secondary herpes simplex virus infection and should be considered as a possible cause of any acute flare of dermatitis. The signs are grouped vesicles and erosions on a weeping dermatitis, with associated fever and malaise. Skin tenderness is more common than itching. A viral swab is needed for diagnosis. Hospital admission may sometimes be required. Staphylococcus aureus commonly colonises but diffuse redness and crusting suggest bacterial infection (see Impetigo). This condition is more often seen in children than adults. Treatment is with antiviral drugs

For more severe disease, use

Initial topical therapy should include wet dressings or compresses with potassium permanganate or aluminium acetate solution. Topical corticosteroids should be avoided until the infection is under control. See Specific treatments for dermatitis.

Herpes simplex infections of the skin and and soft tissue

Herpes simplex labialis (cold sores)

Herpes simplex virus infections are very common in children and adults; on serology over 90% of the population have been exposed to the virus by adult life. The primary attack often occurs in childhood with fever, toxicity and oral ulceration associated with lymphadenopathy. Healing occurs in 2 weeks, but during this time it may be difficult for the child to eat and drink and hospitalisation may be required.

Recurrent attacks usually occur on the lips, but if the primary attack has been on the skin recurrences can occur on that area of skin. Recurrences are usually mild and infrequent, but are occasionally very frequent and disabling. Sun protection is important in preventing recurrences of facial herpes simplex.

In children with atopic dermatitis and in immunosuppressed patients, herpes simplex virus may disseminate, causing a generalised eruption requiring hospitalisation for IV antiviral therapy. In patients with HIV infection, herpes simplex may become chronic with recalcitrant crusted lesions and ulceration. Herpes simplex may be complicated by erythema multiforme, which is often more disabling than the infection itself.

For symptomatic treatment, use

For antiviral therapy, use

Aciclovir may be used in children, both orally and parenterally.

Treatment should be interrupted every 6 months to determine the natural history of the disease in any given patient but may be restarted in the event of recurrence.

Herpetic whitlow

Herpetic whitlow may masquerade as an acute pyogenic infection; see also paronychia.

Mucocutaneous herpes simplex

Aciclovir is recommended for the treatment of acute symptomatic episodes in immunocompromised patients.

For an alternative to parenteral therapy, use

Herpes zoster (shingles)

Acute herpes zoster

Approximately 20% of people will experience herpes zoster (shingles), mostly when they are elderly. Pain due to herpes zoster may occur before, with or following the rash. Postherpetic neuralgia is pain persisting for longer than four weeks after crusting of the vesicles. About 10% of patients with herpes zoster will subsequently have postherpetic neuralgia. Older patients are more likely to experience severe pain and complications. Postherpetic neuralgia occurs in up to 75% of those over 70 years of age affected with herpes zoster.

The aims of treatment are to:

        relieve the acute pain

        prevent postherpetic neuralgia

        decrease the chance of neurological or ophthalmic complications.

Motor effects are not uncommon and usually unimportant, but may on rare occasions be severe. Secondary infection must always be considered and treated if present.

For further information regarding ophthalmic herpes zoster, see Ophthalmic herpes zoster.

If the rash has been present for less than 72 hours, treatment with famciclovir, valaciclovir or aciclovir has been shown to significantly reduce acute pain, the duration of the rash, viral shedding and ophthalmic complications.

Whether antiviral therapy reduces the duration of postherpetic neuralgia remains contentious, although data are suggestive of some benefit. A study has shown that famciclovir reduces the duration of postherpetic neuralgia, especially in patients over 50 years of age. The same may possibly be true for valaciclovir and aciclovir, although the evidence is less clear.

Acute herpes zoster is a greater risk in immunocompromised patients in whom there is an increased risk of dissemination involving skin, adjacent dermatomes and deep tissues and rarely, visceral involvement.

The treatment is effective in anyone; however, it is most useful in those patients:

        treated within 72 hours of the onset of vesicles

        who are immunocompromised

        who are more than 50 years of age

        with severe acute pain

        with involvement of critical areas, eg eye, perineum, limbs, neck.

There is no proven value of antiviral therapy in the immunocompetent patient if it is commenced more than 72 hours after onset of rash.

If there are clear indications for antiviral therapy, then start as early as possible with

famciclovir 250mg orally, every 8 hours for 7 days

OR

valaciclovir 1g orally, every 8 hours for 7 days

OR

aciclovir (child: 20mg/kg up to) 800mg orally, 5 times daily for 7 days.

Herpetic lesions are usually painful. Occasionally pain precedes the rash. The pain is usually mild, but can be intense, especially on the face. In most cases its severity diminishes gradually and resolves completely over a few weeks. Ice packs and protective dressings may provide relief. The elderly are more likely to have severe and/or persistent pain.

aspirin 300 to 600mg orally, every 4 hours as necessary (avoid in children)

OR

paracetamol 0.5 to 1g orally, every 4 to 6 hours as necessary, up to 4g daily

If pain is severe, add

an opioid orally, see Getting to know your analgesics and adjuvants - Opioids.

Although a variety of topical therapies have been used, there is little good supportive evidence. Lignocaine ointment or lignocaine+prilocaine cream may be tried for a few days on nonulcerated skin and even if only partially effective, may supplement other measures. They should not be used on ulcerated skin because of possible systemic toxicity. Occlusive dressings may enhance the efficacy of topical local anaesthetics.

lignocaine 5% ointment or lignocaine+prilocaine cream topically, with an occlusive dressing if possible, to the painful areas. Beware of skin reactions.

There is no proof that systemic corticosteroids alone prevent postherpetic neuralgia or other neurological complications of herpes zoster, but one large study did show that pain and abnormal sleep patterns in the acute phase resolved faster when prednisolone was given in a tapering regimen from 40mg daily over 21 days in combination with aciclovir.

Use of amitriptyline, nerve blocks and opioids, if necessary, soon after the development of acute herpetic pain may also help prevent the sensitisation of the central nervous system that may lead to persistence of the pain, see Dorsal horn of the spinal cord: the gate control theory and central sensitisation. However, the value of the latter measures has yet to be proven.

Postherpetic neuralgia

The pain of postherpetic neuralgia is usually severe. It may present as burning, aching and monotonous pain, or it may present as paroxysmal shock-like stabbing or lancinating pain. The patient almost always has an atypical response (allodynia) of severe pain to a light stimulus, such as gentle brushing of the skin. The skin of the affected area may be depigmented and scarred but the degree of scarring bears no relationship to the severity or quality of pain.

Postherpetic neuralgia is difficult to treat. It is largely a disease of the elderly, in whom consideration must always be given to problems associated with other diseases, particularly those affecting cognition and to the maintenance of physical function and continued socialisation.

Treatment should begin with the simplest and safest approaches, such as aspirin, paracetamol or any NSAID, ice massage, transcutaneous electrical nerve stimulation (TENS), topical capsaicin or lignocaine. If these produce inadequate relief, try either a tricyclic antidepressant (TCA) such as amitriptyline or nortriptyline or an antiepileptic drug such as carbamazepine or gabapentin. It may then be reasonable to try oral opioids.

For pain relief commence with

aspirin 300 to 600mg orally, every 4 hours as necessary (avoid in children)

OR

paracetamol 0.5 to 1g orally, every 4 to 6 hours as necessary, up to 4g daily

OR

any NSAID orally, in the recommended regimens outlined. The elderly are particularly at risk of gastrointestinal toxicity from NSAIDs. Specific COX-2 inhibitors, are safer in this regard and this favours their use in patients aged over 65 years, although they have all the other NSAID adverse effects.

This may be sufficient for some patients without the need for other interventions and is worth trying for a few days.

Ice massage may be helpful.

If the above produce inadequate relief, an early treatment step should be to use TENS. This should be combined with a TCA or an antiepileptic.

transcutaneous electrical nerve stimulation, applied as often as necessary (up to 16 hours a day) for at least 2 weeks.

TCAs are the most effective drug therapy for postherpetic neuralgia, delivering a response rate of around 40% to 65%. Most controlled studies have used amitriptyline. It appears that the ability to block the reuptake of noradrenaline into neurones is important and thus selective serotonin reuptake inhibitors probably have little value in this condition.

Some antiepileptic drugs have proven efficacy in the treatment of postherpetic neuralgia. Either gabapentin or carbamazepine may be used. These may be better tolerated than TCAs in the elderly.

A decision on which drug to use is largely dependent on consideration of efficacy, adverse effects and cost. Other indications, eg need for sedation, or contraindications, eg prostatism, may influence the choice of agent.

Success is more likely if therapy is commenced early. The patient needs to be told that it may take weeks before they experience maximal effect. TCAs should be taken for three to six months after pain is reduced or abolished.

amitriptyline 10 to 25mg orally, at night, increasing every 7 days to a usual maximum dose of 75 to 100mg at night. Use with care in the elderly and those with ischaemic heart disease; if sedation is a problem, an alternative such as nortriptyline or doxepin can be used

OR

carbamazepine 50mg (elderly patient) or 100mg (younger, larger patient) orally, twice daily initially, increasing as tolerated and according to response every 3 days to a maximum of 400mg twice daily. A controlled-release preparation may reduce peak-related toxicity

OR

gabapentin 300mg orally, daily initially, increasing as tolerated and according to response every 4 days from once daily to 3 times daily, to a usual maximum daily dose of 2400mg. Gabapentin is renally excreted and much lower doses should be used in the elderly and those with renal impairment.

Topical therapy with capsaicin, which depletes substance P, or lignocaine ointment, gel or transdermal patch has also been advocated.

capsaicin 0.075% cream topically, 4 times daily. Regular application is necessary for effect; this may present practical difficulties. Response may not occur for a week or more. Severe burning on application can be intolerable for up to one-third of patients. Ice massage or topical local anaesthetic applied 20 minutes prior to capsaicin may help

OR

lignocaine 5% ointment or 10% gel (requires extemporaneous preparation) topically, with an occlusive dressing if possible, to the painful areas

OR

lignocaine 5% patch transdermally, to the painful areas (available in Australia under the Special Access Scheme (SAS) at the time of writing).

An opioid analgesic may be needed for the pain, see Getting to know your analgesics and adjuvants - Opioids. Where possible, this should be under the supervision of a pain clinic, or specialists experienced in their use for this condition. However, patients should not be denied effective analgesia while waiting for an appointment at a pain clinic.

In one trial, intrathecal methylprednisolone given with lignocaine was shown to be effective, in particular in the reduction of allodynia. However, uncertainty remains about possible long-term effects, eg arachnoiditis. Intrathecal corticosteroids are best reserved for patients who do not have a response to any other measures.

Psychological approaches should not be forgotten, see Nonpharmacological pain management techniques.

Many other treatments have been advocated and used. These include other antiepileptic drugs, including phenytoin and sodium valproate, local and systemic corticosteroids and anaesthetic injections, and antipsychotics. None are particularly effective.

Surgical and nerve destruction techniques are not recommended.

Ophthalmic herpes zoster

Aciclovir and related agents decrease pain, corneal damage and anterior uveitis. Early treatment is recommended as soon as the diagnosis is suspected. An ophthalmologist should be consulted. For children, hospital admission is recommended.

If sight is threatened, use

The above treatment may be supplemented with aciclovir 3% eye ointment, 5 times daily.

 Human papilloma virus (warts)

These benign tumours are seen in all ages but are most common in children. Common warts occur mostly on hands, feet and extensor surfaces. Warts on the face often take the form of multiple tiny plane lesions. Warts adjacent to mucosal surfaces are frequently filiform. There is no specific or reliably effective treatment. In children, warts frequently resolve spontaneously, making aggressive therapy inappropriate.

topical keratolytics (over-the-counter preparations of salicylic acid, Upton’s paste) with and without occlusion and serial paring. Normal skin should be covered with adhesive elastic plaster, with a hole left for the wart and the substance applied to the wart. More tape is applied over the top to increase occlusion. The tape is removed the following day and the wart is pared with a scalpel or filed with a pumice stone. When using Upton’s paste on plantar warts, the tape should be left in place for a week.

OR

cryotherapy to each wart every 2 to 4 weeks until resolved

OR

ablative therapy, using cautery and less commonly CO₂ laser, to each wart, but only in situations where scarring is unlikely or unimportant.

Bleomycin has been used by dermatologists. Immunotherapy with topical sensitisers, dinitrochlorobenzene (DNCB) and diphencyprone is effective but can be hazardous because of the risk of severe allergic contact dermatitis and the possible mutagenicity of DNCB. Specialist referral is recommended.

tretinoin 0.05% cream applied daily, particularly for plane warts on the face

OR

cryotherapy to each wart every 2 to 4 weeks until resolved

OR

keratolytics, see above, used with caution on the face: a small area should be tested first and the preparation applied sparingly and accurately.

However, plane warts on the face are very difficult to treat and are often best left untreated.

The treatment of genital warts is discussed in Genital skin diseases.

Topical keratolytics or cryotherapy, see above, may be used.

In general, cautery is useful only in situations where scarring is unlikely or unimportant.

In children with multiple warts, use cimetidine 40mg/kg/day, orally in 2 divided doses for up to 12 weeks. This does not appear to be useful in adults. Cimetidine is thought to act as an immunostimulator. This treatment remains controversial as some trials have shown it to be no more useful than placebo [185-186].

Molluscum contagiosum

This common poxvirus infection is seen often in young children where lesions occur anywhere on the body and in adults where it is seen most often as a sexually acquired infection of the genital area. In human immunodeficiency virus (HIV) infection, lesions may be widespread and atypical. In children, infection is usually acquired from family members or others with whom they swim or bathe. The typical lesion is a pearly papule with a central umbilication and a core that may be extracted with the tip of a needle.

The infection may be complicated by dermatitis, particularly in atopic patients, and by bacterial superinfection. Spontaneous resolution is the rule in immunocompetent patients but may take up to 2 years.

Chemical therapies are ineffective in treating these lesions. In children, conservative management is usually best, unless lesions are widespread and interfering with lifestyle and function. If treatment is required, the most effective treatment is extracting the core with a large needle or curetting the lesions if small. In children with numerous lesions, this may require a general anaesthetic. In adults, cryotherapy is effective.

Treat secondary dermatitis with topical therapy, see General treatment of dermatitis and Control of xerosis.

To avoid secondary infection following extraction, use

mupirocin 2% ointment or cream OR povidone iodine 10% alcoholic solution.

Avoiding heated swimming pools and showering rather than bathing reduces the spread of these lesions. It is not practicable or necessary to isolate children with molluscum contagiosum.

In patients with HIV infection, treatment may be very difficult, although where the lesions are few in number cryotherapy may be effective.

Varicella (chicken pox)

In the nonhospitalised patient with a normal immune system and uncomplicated varicella, antivirals are not recommended because the benefits are only marginal.

In immunocompromised patients with severe disease and in normal patients with complications of varicella, eg pneumonitis or encephalitis, use

For less severe disease, use oral therapy as for herpes zoster.

Superinfection of varicella skin lesions with Streptococcus pyogenes and Staphylococcus aureus may occur and should be treated as for impetigo or cellulitis as appropriate.

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