Can oral iron supplements cause xerosis or pruritus?

Iron and Skin Reactions: Deficiency Causes Itching, Supplementation Rarely Causes Skin Problems

Iron deficiency itself causes generalized pruritus (itching), while oral iron supplements do not typically cause dryness or itchy skin—in fact, iron replacement resolves the itching caused by deficiency. 1, 2

Iron Deficiency as a Cause of Pruritus

The most important clinical point: iron deficiency is a well-established systemic cause of generalized itching without any visible rash. 1, 2, 3

• Iron deficiency anemia was the most common systemic cause of generalized pruritus in a prospective study of 55 patients presenting to dermatology, accounting for more cases than thyroid disease, malignancy, or liver disease. 4
• The British Association of Dermatologists explicitly lists "disorders of iron metabolism" (both deficiency and overload) as documented causes of generalized pruritus without underlying dermatosis. 1
• Iron replacement therapy leads to complete cessation of pruritus within days to weeks after starting treatment—symptoms typically begin improving 2-10 days after initiating iron supplementation and resolve completely within 2-3 weeks. 1, 2, 5

Diagnostic Approach

• Full blood count and serum ferritin should be checked in all patients with chronic generalized pruritus, even when no rash is visible (Strength of recommendation C). 1, 2
• Ferritin can be falsely elevated during inflammation (it is an acute-phase reactant), so comprehensive iron studies including serum iron and total iron binding capacity should be obtained if iron deficiency is suspected despite "normal" ferritin. 1, 3

Oral Iron Supplements and Skin Reactions

Oral iron supplements do not cause xerosis (dry skin) or pruritus as typical side effects. The most common adverse effects of oral iron are gastrointestinal: constipation, diarrhea, and nausea. 1

Rare Hypersensitivity Reactions

• True allergic reactions to oral iron salts are extremely rare but have been documented in isolated case reports, presenting as anaphylaxis rather than isolated pruritus or dry skin. 6
• When hypersensitivity does occur, it typically manifests as systemic anaphylactic symptoms (not localized skin dryness or itching), and requires desensitization protocols with antihistamine coverage. 6

Intravenous Iron Considerations

• Cutaneous hypersensitivity reactions to IV iron formulations (iron sucrose, ferric carboxymaltose, etc.) are possible but rare, occurring in less than 1 in 250,000 administrations with modern formulations. 1, 7
• These reactions present as acute or delayed cutaneous hypersensitivity, not as xerosis or chronic pruritus. 7

Clinical Algorithm

When a patient on iron supplements reports itchy or dry skin:

1. First, determine if the pruritus preceded or followed iron supplementation. 1, 4

   • If pruritus existed before starting iron: the underlying iron deficiency is the cause, and symptoms should improve with continued supplementation. 2, 5
   • If pruritus began after starting iron: consider other causes (see below). 1

2. Evaluate for alternative causes of pruritus unrelated to iron therapy: 1

   • Xerosis (dry skin) from environmental factors, aging, or inadequate moisturization 8
   • Drug-induced pruritus from other medications (12.5% of drug reactions present with pruritus) 9
   • Other systemic causes: renal disease, liver disease, thyroid disorders, malignancy 1, 9

3. If true iron hypersensitivity is suspected (extremely rare): 6

   • Perform controlled oral challenge and skin testing with iron salts
   • Consider desensitization protocol if iron therapy is essential
   • Alternative: switch to IV iron formulations (though these also carry rare hypersensitivity risk) 1, 7

Key Clinical Pitfalls

• Do not discontinue iron supplementation in a patient with iron-deficiency pruritus who develops itching—the itching is from the deficiency itself, not the treatment, and will worsen if iron is stopped. 5
• Do not attribute all pruritus in iron-deficient patients to the deficiency alone—iron overload can also cause pruritus, so verify that the patient is truly deficient before assuming causation. 1
• Remember that in polycythemia vera, iron deficiency paradoxically causes severe pruritus—iron supplementation relieves symptoms but must be carefully monitored to avoid dangerous increases in red cell mass. 5
• Xerosis management requires emollients with both rehydrating and lipid-replenishing components (preferably water-in-oil formulations for very dry skin, with ingredients like urea for scaling or polidocanol for pruritus)—this addresses dry skin regardless of iron status. 8