The search terms used included “atopic dermatitis AND (hyperkalemia OR hyponatremia OR electrolyte imbalance OR pseudohypoaldosteronism).” The results of this extensive search revealed 36 cases of severe AD with hyponatremia, which were associated with a tendency to present with hyperkalemia, metabolic acidosis, and increased renin-angiotensin-aldosterone activity. This evidence concerns the gene REN and pseudohypoaldosteronism.