We compared the clinical features, histopathology, immunopathology and immunogenetics of 30 patients with toxic erythema of pregnancy and 24 patients with herpes gestationis. Although we found some clinical and histopathological overlap we highlighted several important differences. In toxic erythema of pregnancy prominent striae were frequently present. Herpes gestationis was suggested by the occurrence of periumbilical lesions, acute exacerbations immediately after delivery, and persistence of the eruption for more than 3 weeks post-partum. In herpes gestationis, immunofluorescence studies were consistently positive, there was a high frequency of HLA-B8 and an association with autoimmune thyrotoxicosis. Toxic erythema of pregnancy did not share these immunological features. Therefore we feel that toxic erythema of pregnancy and herpes gestationis should continue to be classified as separate disorders.

In this study we present a patient with the sublamina densa type of linear IgA bullous dermatosis (LABD), with IgA autoantibodies reactive with the 290-kDa type VII collagen (the epidermolysis bullosa acquisita (EBA) antigen) and with immunoblotting of normal human dermal extracts. The clinical and histological features of the present case were compatible with those of LABD but quite different from those of EBA. Although EBA sera reacted with the bacterial fusion protein of the N-terminal globular (NC1) domain of type VII collagen, this patient's serum did not show reactivity. Furthermore, ultrastructural localization of target epitopes on the anchoring fibrils in this patient was considerably different from EBA. These results indicate that, whereas EBA antibodies react with the NC1 domain of type VII collagen, the epitope in this case is different from that of EBA (and is most likely on the central triple helical domain). This difference may be responsible for the clinical presentation in this patient being distinct from that of EBA.

Acquired autoimmune bullous diseases of childhood are rare, and can be difficult to distinguish clinically. We have studied 12 children, with an initial diagnosis of bullous pemphigoid (BP) in eight patients, cicatricial pemphigoid (CP) in one, chronic bullous disease of childhood (CBDC) in one, and epidermolysis bullosa acquisita (EBA) in two. All patients had positive indirect immunofluorescence (IIF) of the BMZ with IgG. Using 1 M NaCl split skin, six patients showed epidermal binding of IgG, with additional IgA in three cases, and in five patients IgG antibodies bound a dermal protein. Immunoblotting studies revealed an antibody to type VII collagen (EBA antigen) in three patients who had a dermal pattern on IIF. Six sera reacted with an epidermal protein of 180 and/or 220 kDa, characteristic of BP and CP. One of the three IgA-positive sera detected 220- and 180-kDa epidermal proteins using anti-IgA antibody. Following these studies the diagnosis was changed in three of the children. The diagnosis of CBDC was changed to either BP or EBA because of the presence of circulating IgG autoantibodies. In two children with an initial diagnosis of BP the diagnosis was changed to EBA. We conclude that the clinical picture in bullous disorders of childhood shows considerable overlap, and is often misleading. Additional circulating IgA autoantibodies seem to be more common in BP than has been recognized previously. Indirect immunofluorescence investigation on 1 M NaCl split skin may be helpful in differentiating between BP and EBA, but does not replace immunoblotting studies. EBA is apparently more common in children than in adults. No difference was found between the children with BP and EBA with regard to the duration of disease. The long-term outlook is good, although the course may be protracted.

Summary Eighteen patients with benign chronic bullous dermatosis of childhood were studied and the findings compared with those of dermatitis herpetiformis (twenty‐two cases) and bullous pemphigoid (five cases) beginning in childhood. The patients with benign chronic bullous dermatosis of childhood had a moderately pruritic bullous eruption with maximal involvement of the pelvic and perioral regions which tended to occur at an earlier age than either dermatitis herpetiformis or bullous pemphigoid. In contrast to dermatitis herpetiformis one‐third of the cases with benign chronic bullous dermaiosis of childhood went into remission. Evidence of coeliac disease was only found in the dermatitis herpetiformis group. Surprisingly both diseases shared HLA‐B8. A linear BMZ band of IgA was detected on direct immunofluorescence in all but one of the cases with benign chronic bullous dermatosis of childhood and circulating antibodies were detectable in two‐thirds. Routine histopathology was of little value in distinguishing between benign chronic bullous dermaiosis of childhood and dermatitis herpetiformis or bullous pemphigoid. Several paradoxes have yet to be explained before it can be determined whether benign chronic bullous dermatosis of childhood is a variant of dermatitis herpetiformis or linear IgA disease.

Clinical and immunopathological studies of three patients with lichen planus pemphigoides (LPP) were carried out to investigate the relationship between LPP and bullous pemphigoid (BP) and to determine whether the antigen in LPP is the classical BP antigen. LPP is usually considered to be the coexistence of lichen planus with BP. The bullae in LPP were subepidermal and indistinguishable from BP. Indirect immunofluorescence demonstrated antibody binding to the epidermal surface of 1 M NaCl-split skin and mucosae, as in BP. The tissue distribution of the LPP antigen mirrored the distribution of BP in stratified squamous epithelia but was absent from transitional epithelia (pig bladder). Immunoelectron microscopy, both direct (two cases) and indirect (one case), showed binding to the lamina lucida as with BP antigen. Western blotting of epidermal extracts using the patients' sera showed that instead of reacting with the classical bullous pemphigoid antigen (220 kDa in our series), the antisera reacted with a unique band of 200 kDa in addition to the band of 180 kDa found as a minor antigen in bullous pemphigoid, but more commonly in pemphigoid gestationis. The relationship between these antigens awaits molecular characterization. These findings suggest that the target antigen in LPP may be unique.

Histopathological criteria were used to classify twenty-four patients with chronic urticaria into three groups, which were then studied to establish whether circulating immune complexes (CICs), complement activation and deposition of immunoreactants are confined to patients with urticarial vasculitis. Group I (three patients) had classical urticarial vasculitis, and two of these patients showed hypocomplementaemia with evidence of C3 conversion and deposition of immunoreactants in lesional and uninvolved skin. Ten patients (group 2) with a dense perivascular mixed-cellular infiltrate had normal or raised complement levels and infrequent evidence of C3 conversion. Immunoreactants were detected only in their lesional skin. Eleven patients (group 3) had only a sparse perivascular infiltrate. In this group, complement was normal and immunofluorescence was essentially negative. Cryoglobulins were detected in group I patients only. Monoclonal rheumatoid factor and C1q binding were positive in all group I patients, half the group 2 patients and none of the group 3 patients. This study suggests that urticaria and urticarial vasculitis form a disease continuum, and identifies a group of patients with features intermediate between urticarial vasculitis and ordinary urticaria.

The immunobullous diseases bullous pemphigoid (BP) and epidermolysis bullosa acquisita (EBA) are very rare in childhood. Although case studies have been detailed, there are no reports of a large series of patients documenting the effectiveness of treatment and long-term prognosis. We report the clinical presentation, immunopathologic features, disease course, and long-term prognosis of BP and EBA in a series of 11 children. The initial diagnoses based on clinical features were BP (5), EBA (3), and chronic bullous disease of childhood (CBDC) (3). These were subsequently revised from BP to EBA (2), CBDC to BP (2), and CBDC to BP or EBA (1) following the results of direct and indirect immunofluorescence and immunoblotting. Analysis of IgG subclasses in eight cases showed that the predominant subclasses were IgG1 (8) and IgG4 (6). The clinical features appeared to be highly variable, and in patients presenting with inflammatory blistering, laboratory studies were required in order to differentiate between BP and EBA. All patients improved on treatment with corticosteroids and/or sulfones, although treatment regimens showed wide variation. Their diseases tended to remit within 2 years, and their long-term prognosis was good.

During the period 1985-88, 30 children with a chronic blistering dermatosis were studied. Of these 25 were found to have chronic bullous dermatosis of childhood (CBDC) and five had bullous pemphigoid (BP). No case of dermatitis herpetiformis (DH) was seen in the same period. Except for the difference in immunofluorescence (IMF) there were no definite clinical, histological or therapeutic differences between the two groups. All the children were Africans with the exception of one Indian girl. Their ages ranged from 1 year to 12 years with a mean of 5 years. The females outnumbered the males in a ratio of 3:2. All children had a generalized eruption consisting of large tense blisters arising on normal skin. The blisters were more profuse on the lower trunk, pelvic region and limbs. Face and scalp were also affected. Histological features of BP and DH were seen. Direct IMF in the CBDC patients showed linear deposits of IgA at the basement membrane zone (BMZ) while linear deposits of IgG were seen in the BP group. Complement and IgM were also seen in some cases in both groups. Sixty per cent of the CBDC patients showed IgA BMZ antibodies by indirect IMF. There were no symptoms or signs of malabsorption. Serum vitamin B12 and folate levels were normal. HLA studies showed the B-8 antigen in five of the 20 patients studied. Therapy was difficult in most cases. All patients haemolysed on therapeutic doses of dapsone, sulphapyridine and/or prednisone had to be added. Follow-up was generally poor as six patients failed to return after discharge from hospital.(ABSTRACT TRUNCATED AT 250 WORDS)