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Vitamin B6 deficiency
Other Resources UpToDate PubMed

Vitamin B6 deficiency

Contributors: Rajini Murthy MD, Abhijeet Waghray MD, Marilyn Augustine MD, Paritosh Prasad MD, Susan Burgin MD
Other Resources UpToDate PubMed


Vitamin B6 (pyridoxine) is a water-soluble vitamin absorbed in the jejunum that is present in many foods, including whole grains, vegetables, fish, and meats. Pyridoxine is involved in over 100 different enzyme reactions in the body. These include amino acid metabolism, heme and neurotransmitter synthesis, and the metabolism of glycogen, lipids, and steroids.

Pyridoxal phosphate (PLP) is the most biologically active form of pyridoxine in the body.

Isolated vitamin B6 deficiency is uncommon and usually occurs in conjunction with other vitamin deficiencies. Alcohol use disorder; malabsorption syndromes; eating disorders, which result in general undernutrition; or medications (eg, isoniazid, theophylline, penicillamine, oral contraceptives) predispose patients to the development of pyridoxine deficiency.

Drugs induce vitamin B6 deficiency in various ways. For example, isoniazid binds to PLP, resulting in increased excretion of the active form of B6. Penicillamine inhibits vitamin B6-dependent enzymes. Oral contraceptives play a role in the increased turnover of vitamin B6.

Manifestations of pyridoxine deficiency are often nonspecific but may include fatigue, nausea, anorexia, paresthesia, depression, glossitis, dermatitis, peripheral neuropathy, and microcytic anemia. Severe vitamin B6 deficiency can result in seizures and personality changes characterized by irritability and confusion.

In infants, B6 deficiency may lead to diarrhea, seizures (pyridoxine-dependent seizures), and anemia.


E53.1 – Pyridoxine deficiency

386080007 – Vitamin B6 deficiency

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Beriberi
  • Folate deficiency
  • Pellagra
  • Vitamin B12 deficiency
  • Seborrheic dermatitis 
Differential diagnosis of intertrigo:
  • Candidiasis – satellite papules and/or pustules
  • Inverse psoriasis – well-demarcated salmon-pink plaques
  • Tinea cruris – annular scaly plaques
  • Allergic contact dermatitis or Irritant contact dermatitis
  • Erythrasma
  • Acanthosis nigricans
  • Lichen sclerosus
  • Hailey-Hailey disease – macerated plaques with linear erosions
  • Extramammary Paget disease
  • Group A beta-hemolytic streptococcal intertrigo
  • Langerhans cell histiocytosis
  • Lichen planus pigmentosus
  • Granular parakeratosis
  • Hidradenitis suppurativa
  • Fox-Fordyce disease

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Reviewed:10/17/2022
Last Updated:10/30/2022
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Vitamin B6 deficiency
A medical illustration showing key findings of Vitamin B6 deficiency (Adult)
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