Any of the above infections often exacerbate AD, and control of infection is essential before the dermatitis can be treated effectively. A bacterial swab of involved skin is a useful, inexpensive test that confirms infection and determines antibiotic sensitivities. Community acquired methicillin-resistant S. aureus is becoming more common and often requires treatment with clindamycin. If herpes simplex is suspected clinically by the presence of grouped vesicles or erosions, viral swabs should be taken. This is always an acute, and sometimes also recurrent, event. When the infection is widespread, treatment with aciclovir or valaciclovir is needed and specialist referral recommended.
Molluscum contagiosum infection, although by no means confined to children with dermatitis, does often make the dermatitis refractory to treatment. The best way to eradicate the lesions is to remove them physically; however, this is often easier said than done. It can be difficult to change the course of the infection and one may have to accept that until the lesions resolve spontaneously, more aggressive treatment of the dermatitis may be necessary.
In many cases, the child’s skin is chronically colonised by S. aureus. This can result in exacerbation of the dermatitis, difficulty in controlling it, and crusting and folliculitis. When any of these are encountered, cutaneous and nasal bacterial swabs should be taken to confirm the infection and determine the sensitivities of the S. aureus. This situation requires more than one course, and at times repeated courses, of oral antibiotics. Adding bleach to the bath water has been shown to be very effective in controlling chronic bacterial skin infection.8 A topical antibiotic such as mupirocin 2% ointment should be kept on hand to apply to crusted areas twice daily for a week. It is more effective if the crusts are removed by soaking under a wet cloth or in the bath. If nasal carriage is detected, mupirocin 2% nasal ointment should also be used twice daily for seven days.
Dicloxacillin or flucloxacillin are the treatments of choice for obvious secondary infection, but cefalexin or roxithromycin are useful for patients who are allergic to penicillin. Many strains of S. aureus are resistant to erythromycin. In some children in whom chronic infection makes AD impossible to control, long-term oral antibiotic treatment may be useful. However, before embarking on this, specialist referral is recommended.
Treating the dermatitis/psoriasis combination
Patients with a combination of dermatitis and psoriasis need treatment for both conditions. Therefore, in addition to the usual management of AD, tar creams and shampoos or topical calcipotriol may be needed. It is important that the parent understands which areas of the rash are AD and which are psoriasis. Managing this situation can be difficult, and referral to a dermatologist is recommended; this often happens anyway because the ‘dermatitis’ does not respond to treatment.
Investigation and management of allergy
Most parents of children with AD want to know why they have it, and the answer, ‘It’s genetic’, is not enough. As a result, many will request allergy testing. The thought that they may find a substance that if avoided will end the problem is very attractive and also gives them something tangible that they can control without the use of drugs. Further, parents who think their child has an inherited health problem often feel unnecessarily guilty and one response to this is denial of the diagnosis.