Treatment of infection in atopic dermatitis

Atopic skin is particularly susceptible to bacterial infection (eg staphylococci, streptococci) and viral infection (eg Herpes simplex virus, molluscum contagiosum virus, human papillomavirus [warts]). Patients with dermatitis have higher rates of skin staphylococcal carriage than those with normal skin. Infection stimulates further inflammation and reduces the effectiveness of topical treatments.

Take cutaneous bacterial swabs for cultures and susceptibility testing if:

• significant crusting or pustules are present
• dermatitis is flaring or persistent despite appropriate topical therapy.

Also take a viral swab if herpes simplex virus infection (eg eczema herpeticum) is suspected (eg grouped vesicles, punched-out erosions).

Use of antibiotics in noninfected atopic dermatitis does not provide therapeutic benefit. Ideally, only use antibiotics if infection is microbiologically confirmed and if there are clinical signs of infection. However, empirical antibiotic treatment may be started while waiting for microbiology results.

Depending on severity of the infection, bleach baths or soaks can be used alone or in combination with antibiotics. For example, for milder infections, bleach soaks (eg for localised infections of the hands and/or feet) or bleach baths (for widespread infection) alone can be used. For more severe infections, antibiotics (eg topical mupirocin, dicloxacillin, flucloxacillin) can used in conjunction with bleach soaks or baths.

For milder infections, bleach baths or soaks alone can be used. Different brands of household bleach vary in strength; check the label to confirm the strength. Standard White King household bleach in Australia has a sodium hypochlorite concentration of 4.2% (42 g/L). Use unfragranced bleach preparations because allergies can occur to fragrances.

For a standard average-sized bath (80 litres), use 1/4 (quarter) cup of bleach. For smaller baths (eg to soak hands or feet), measure the capacity of the bath using a bucket (a standard sized bucket is usually 10 litres), and add bleach to make a final concentration of 10 mL per 10 litres (eg for a 15 litre bath, add 15 mL of bleach).

If there is a bleach smell, the concentration of the bleach bath or soak may be too high.

After preparing the bleach bath or soakThe Royal Children's Hospital (RCH) Melbourne, 2020:

• soak affected body parts in the water for 10 minutes
• for a bleach bath, wash the head and face with the water, but do not immerse head
• use a soft disposable towel to wipe away any crusting or weeping at the infected area while in the water
• do not rinse the skin after soaking
• dry the skin with a towel (use old or white towels to avoid bleaching coloured towels)
• apply an emollient because bleach baths and soaks can worsen dry skin.

Bleach baths or soaks can be used twice weekly.

For more severe infections, antibiotics can be used in conjunction with bleach baths or soaks.

For localised infection of atopic dermatitis, use topical antibiotics:

For widespread infection of atopic dermatitis, use oral antibiotics. Until results of cultures and susceptibility testing are available, use:

Cefalexin is often preferred in children because the liquid formulation is better tolerated. It is also used for patients who have had a nonsevere (immediate or delayed) hypersensitivity reaction to a penicillin¹. Use:

For patients who have had a severe (immediate or delayed)² hypersensitivity reaction to a penicillin, use: