Drug-Induced IgA Deficiency

 

Clinical features:

(1) normal serum IgA concentration prior to therapy

(2) drop in IgA concentration during drug therapy

(3) return of serum IgA levels to previous levels on discontinuation of the implicated drug

 

Drugs implicated:

(1) phenytoin

(2) D-penicillamine

(3) sulfasalazine

(4) zonisamide

(5) gold therapy

 

Some patients may develop a concurrent drug-induced deficiency of other immunoglobulins (IgG2, IgM, other).

 

A few patients may have sufficient hypogammaglobulinemia to develop complications such as increased bacterial infections.

 

Differential diagnosis:

(1) pre-existing selective IgA deficiency

(2) other causes of hypogammaglobulinemia