Skin changes in vitamin B12 deficiency
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Skin Hyperpigmentation in Vitamin B12 Deficiency
Skin hyperpigmentation is the most common skin change seen in vitamin B12 deficiency. It often appears on the hands, feet, knuckles, palmar creases, elbows, knees, and sometimes the face, resembling melasma. This pigmentation can be generalized or localized and is sometimes the first or only sign of deficiency, even before anemia or neurological symptoms develop. The pigmentation is thought to result from increased melanin production, possibly due to decreased glutathione levels and enhanced tyrosinase activity in the skin. Importantly, this hyperpigmentation is usually reversible with vitamin B12 supplementation 12345678+1 MORE.
Other Cutaneous Manifestations: Vitiligo, Hair, and Oral Changes
Besides hyperpigmentation, vitamin B12 deficiency can cause other skin and mucosal changes. These include:
- Vitiligo (depigmentation): Some patients develop patches of depigmented skin, though this is less common than hyperpigmentation 1679.
- Hair changes: Patients may notice hair discoloration or premature graying, and in some cases, hair loss 179.
- Angular cheilitis and glossitis: Cracking at the corners of the mouth (angular cheilitis) and inflammation of the tongue (glossitis) are also reported 179.
Mechanisms Behind Skin Changes in Vitamin B12 Deficiency
The skin changes in vitamin B12 deficiency are linked to its role in DNA synthesis and cellular metabolism. Deficiency leads to incomplete cell maturation, which can affect skin and hair cells. The increase in skin pigmentation is believed to be due to increased melanin synthesis rather than a defect in melanin transport. This is supported by histological findings showing more melanin in the basal layer of the skin and increased melanosomes in melanocytes and keratinocytes 238.
Importance of Early Recognition and Treatment
Cutaneous signs of vitamin B12 deficiency can appear before more serious symptoms like anemia or neurological problems. Recognizing these early skin changes is important because prompt vitamin B12 supplementation can reverse the skin findings and prevent long-term complications 14689.
Skin Changes in Special Populations
In infants, especially in regions where vitamin B12 deficiency is more common, skin changes are frequently observed but may be overlooked due to more prominent neurological or blood-related symptoms . In adults, dietary habits (such as strict vegetarianism), malabsorption, or previous gastric surgery can increase the risk of deficiency and related skin changes 57.
Conclusion
Vitamin B12 deficiency can cause a range of skin changes, most notably hyperpigmentation, but also vitiligo, hair changes, and oral lesions. These signs are often reversible with treatment and can serve as early warning signs for clinicians to diagnose and manage vitamin B12 deficiency before more severe complications develop 12345678+2 MORE.
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