What vitamin B deficiency is associated with a magenta tongue and desquamation?

Magenta Tongue and Desquamation: Riboflavin (Vitamin B2) Deficiency

The answer is A. Riboflavin deficiency is the classic cause of magenta tongue with desquamation, manifesting as glossitis with characteristic oral-buccal lesions including cheilosis, angular stomatitis, and seborrheic dermatitis. 1

Clinical Presentation of Riboflavin Deficiency

Riboflavin deficiency presents with a distinctive constellation of mucocutaneous findings:

• Oral-buccal lesions including glossitis (magenta-colored tongue), cheilosis (cracking at corners of mouth), and angular stomatitis are the hallmark features 1
• Seborrheic dermatitis affecting the face, trunk, and scrotum accompanies the oral findings 1
• Ocular manifestations such as itching, burning, dryness, corneal inflammation, and photophobia may be present 1
• Hematologic changes including normochromic, normocytic anemia and marrow aplasia can occur 1

The characteristic magenta (purplish-red) discoloration of the tongue with papillary atrophy distinguishes riboflavin deficiency from other B vitamin deficiencies 2, 3.

Distinguishing Features from Other B Vitamin Deficiencies

Understanding the specific tongue presentations helps differentiate between B vitamin deficiencies:

• Thiamine (B1) deficiency causes beriberi with neuritis, edema, and cardiac failure, but does not characteristically produce magenta tongue 1
• Pyridoxine (B6) deficiency presents with glossitis, but typically without the magenta coloration, along with dermatitis, cheilosis, and peripheral neuritis 1
• Cobalamin (B12) deficiency produces atrophic glossitis but the tongue appearance differs from the magenta color seen in riboflavin deficiency 3, 4
• Niacin (B3) deficiency causes pellagra with the classic triad of dementia, diarrhea, and dermatitis 1

Pathophysiology and Associated Deficiencies

Riboflavin deficiency rarely occurs in isolation:

• Riboflavin deficiency is frequently associated with pyridoxine, folate, and niacin deficiencies with their overlapping symptoms 1
• Multiple nutritional deficiencies commonly coexist, complicating the clinical picture 5
• Riboflavin plays a critical role in the metabolism of other B vitamins, particularly folate and vitamin B6, so its deficiency can impair their function 6

Diagnostic Approach

When evaluating suspected riboflavin deficiency with magenta tongue:

• Hematologic screening including complete blood count, red-cell indices, serum iron, B12, and folate levels should be performed to identify multiple deficiencies 5
• Erythrocyte glutathione reductase activity test is the most reliable functional assay for riboflavin status, especially in the context of inflammation 1
• Red blood cell FAD measurement is another validated method, particularly when inflammation is present 1
• Clinical diagnosis should not rely on appearance alone, as multiple deficiencies often coexist 5

Treatment Considerations

Management of riboflavin deficiency requires prompt supplementation:

• Oral riboflavin 5-10 mg/day is the standard treatment for deficiency 1
• IV administration of 160 mg riboflavin for four days may be necessary in cases of clinical deficiency with severe manifestations 1
• Prompt resolution of lesions after therapeutic doses confirms the diagnosis 2
• Parenteral nutrition should provide 3.6-5 mg riboflavin per day for patients requiring nutritional support 1

High-Risk Populations

Certain patient groups require vigilance for riboflavin deficiency:

• Patients with malabsorption syndromes (short bowel syndrome, celiac disease) 1
• Those with chronic conditions including thyroid dysfunction, diabetes, renal disease (pre-dialysis, hemodialysis, peritoneal dialysis) 1
• Patients with alcoholism, and during pregnancy, lactation, and in the elderly 1
• Individuals with surgery, trauma, burns, or fractures, and those on psychotropic drugs, tricyclic antidepressants, or barbiturates 1
• Patients with anorexia nervosa who avoid dairy products 1