Linear IgA Disease: Definition, Etiology, Clinical features, diagnosis, D/D, Rx
Linear immunoglobulin A (IgA) disease is a disorder that has recently been recognized in the spectrum of chronic bullous diseases, characterized by the linear deposition of IgA along the basement membrane zone.
Linear IgA disease is a rare disease that occurs in two forms. The juvenile form seen in children and teenagers involves the skin of the lower back, genital area, and perioral area but not the oral cavity. The adult forminvolves the skin of the trunk, limbs, face, and the oral mucosa. It is not considered part of the pemphigoid group but is a similar disease in which autoantibodies attack basement membrane proteins. The main distinction of linear IgA disease is that the autoantibody is in the IgA class of immunoglobulins, whereas in the pemphigoid group it is primarily IgG.
Clinical features :
- The disease is more common in women than in men
- Usually occurs between the ages of 40 and 50 years
- Children may also be affected
- relatively mild symptomatology, usually itching or a burning sensation.
- It will most often produce skin lesions, but oral mucosal and ocular lesions can occur simultaneously in the adult form.
- Oral lesions occur in about 20–30% of cases
- Characterized by the formation of bullae that soon rupture, leaving superficial, nonspecific ulcerations.
- The skin lesions consist of bullae that rupture, forming ulcerations covered by crusts.
- Scarring conjunctivitis may also occur.
- The clinical features of the disease are similar to those seen in cicatricial pemphigoid.
Laboratory tests :
Histopathological examination, direct and indirect immunofluorescence
Differential diagnosis :
- Cicatricial pemphigoid,
- bullous pemphigoid,
- dermatitis herpetiformis,
- pemphigoid gestationis.
Mild cases may require no specific treatment. If symptoms are more prominent or if ocular involvement occurs, linear IgA disease is treated with either dapsone or prednisone. If ocular lesions are present, an ophthalmology consultation is indicated.