Atopic eczema
Atopic eczema is the commonest skin problem presenting in pregnancy. It can be severe and life ruining, and life threatening if secondary infection with herpes simplex (eczema herpeticum) or Streptococcus occurs. The effect of pregnancy on pre-existing atopic eczema is unpredictable: the immunosuppression can lead to improvement, but often there is deterioration of the eczema. The eczema becomes more widespread and may result in erythroderma in the most severe cases. Secondary infection with Staphylococcus aureus and Streptococcus is a frequent complication. The skin is red, dry, and scaly with areas of excoriation and thickening or lichenification.

Treatment is a major problem in pregnancy, as there is a dilemma in balancing the need for treatment with the wish to minimize the use of potent topical steroids which will be absorbed and may affect the foetus.

The use of emollients may lessen the requirements for topical steroids, and steroids should be used in the minimum quantities and strengths necessary to control the disease (

see Table 1). Many topical steroids contain antiseptics and antibiotics which will be absorbed and may be contraindicated in pregnancy. The sedating antihistamine, chlorpheniramine, may help with sleep. Secondary infection often requires systemic antibiotics such as erythromycin or flucloxacillin.

Psoriasis
Psoriasis may improve or deteriorate during pregnancy. Therapy poses special problems as all the systemic treatments are contraindicated: methotrexate is a folic acid antagonist, acitretin is teratogenic, ciclosporine results in intrauterine growth retardation, and psoralens with UVA are still not proven to be safe. Topical therapy with steroids should be avoided if possible. Coal tars and dithranol have been widely used in pregnancy but are not proven to be safe, and the new vitamin D analogues are not licensed for use in pregnancy. The ideal is minimum treatment, with emollients and if necessary UVB.

A severe form of pustular psoriasis, impetigo herpetiformis, may occur in pregnancy and is best managed with bedrest and emollients.

Autoimmune dermatoses in pregnancy

Cutaneous lupus erythematosus
Cutaneous lupus erythematosus does not seem to be adversely affected or improved by pregnancy. However such patients should be screened for anti-Ro and anticardiolipin antibodies etc., preferably prior to conception, to identify at-risk pregnancies.

Autoimmune bullous diseases
Linear IgA disease, an autoimmune blistering disease with IgA basement membrane zone antibodies, usually improves with pregnancy, such that some patients can discontinue their dapsone therapy. Despite the deposition of immunoreactants in the amnion basement membrane zone the fetus is not adversely affected. There is usually an exacerbation 3 months postpartum.

Pemphigus vulgaris, an autoimmune blistering disease with widespread mucosal and cutaneous erosions caused by antibodies to desmosomal components, can be transmitted across the placenta, with devastating results to the fetus. This does not occur in the related pemphigus foliaceus, which is endemic in Brazil.