Why does iron deficiency provoke a desire to chew ice in patients, particularly women of childbearing age or those with a history of gastrointestinal disorders?

Why Iron Deficiency Provokes Ice Craving (Pagophagia)

The Phenomenon

Ice craving (pagophagia) is a recognized clinical manifestation of iron deficiency that typically resolves with iron replacement therapy before hemoglobin levels fully normalize, though the exact mechanism remains incompletely understood. 1, 2

Proposed Mechanism

The most plausible explanation for why iron-deficient patients specifically crave ice relates to potential relief of oral or glossal inflammation from the cold sensation 2. This theory is supported by the fact that:

• Iron deficiency commonly causes oral manifestations including angular stomatitis and glossitis (inflammation of the tongue) 1, 2
• The cold temperature of ice may provide symptomatic relief from these inflammatory changes 2
• Pagophagia improves non-hematologic symptoms of iron deficiency such as stomatitis and glossitis 3

Clinical Characteristics

Prevalence and Demographics

• Pagophagia occurs in 58% of patients with iron deficiency anemia due to gastrointestinal blood loss 4
• It is significantly more common in women (68%) than men (39%) 4
• Among patients with pica behaviors, 88% manifest specifically as ice eating rather than other non-nutritive substances 4

Behavioral Pattern

• Patients may consume massive quantities, ranging from 250-500g daily to as much as 10-12kg per day in severe cases 5
• The behavior is compulsive and patients often feel relief only after ice consumption 5
• Patients may be secretive or reluctant to mention their ice-eating habit, and most physicians are unaware of pica, leading to missed diagnoses 6

Clinical Significance

Diagnostic Value

• Pagophagia is a specific clinical manifestation that should prompt iron studies, particularly serum ferritin (the most powerful test for diagnosing iron deficiency) 2
• However, the presence of pagophagia is not useful for predicting the underlying cause of bleeding (such as distinguishing malignancy from other sources) 4

Resolution with Treatment

• Ice craving characteristically resolves with iron replacement therapy before hemoglobin levels fully normalize, distinguishing it from the anemia itself 2
• This early resolution supports the hypothesis that pagophagia relates to tissue iron deficiency rather than anemia per se 2

Potential Complications

• Excessive ice consumption can lead to severe hyponatremia and seizures from water intoxication 6
• Patients may present with polyuria that goes undiagnosed if the ice-eating behavior is not elicited 6

High-Risk Populations

Pagophagia should be specifically screened for in:

• Women of childbearing age with menstrual blood loss (requiring an additional 0.3-0.5 mg iron daily) 1
• Patients with gastrointestinal disorders causing chronic blood loss 4
• Post-bariatric surgery patients, particularly after Roux-en-Y gastric bypass, who develop malabsorption 7
• Patients on chronic proton pump inhibitors causing hypochlorhydria and impaired iron absorption 1, 8

Clinical Approach

Screening Strategy

Explicitly ask about ice-eating behavior in all patients with suspected iron deficiency, as patients often don't volunteer this information and may not consider it abnormal 6, 7. Probe subtly about:

• Daily ice consumption patterns 7
• Compulsive behaviors around ice or freezer frost 5
• Addition of excessive ice to drinks 6

Diagnostic Workup

When pagophagia is identified:

• Perform iron studies including serum ferritin 2
• Investigate underlying causes of iron deficiency, particularly gastrointestinal blood loss in men and postmenopausal women 1
• Consider celiac disease screening (found in 3-5% of iron deficiency cases) 1, 8
• Assess for medication-related causes including NSAIDs and chronic PPI use 8