Introduction
Macronutrient and micronutrient deficiencies cause several skin and nail changes. Macronutrients are carbohydrates, lipids, and proteins, whereas micronutrients are vitamins and minerals. Vitamin and nutritional deficiencies are most typically caused by poverty, restricted diets, medication, alcoholism, and low dietary intake in the elderly and ill in industrialized countries. Identifying abnormalities in the skin and nails can be a useful diagnostic technique for underlying nutritional deficiencies. Macronutrient deficiencies are quite rare in developed countries. Because many foods are high in carbohydrates, protein, and essential fatty acids, deficiencies are more common than carbohydrate deficiencies. Because these nutrients are the building blocks of these tissues, insufficient vital fatty acids and proteins also lead to problems with the skin and nails.
What are the Dermatological Impacts of Rare Nutritional Deficiencies?
Vitamin deficiency:
Vitamin deficiency is a common cause of various dermatological problems. Water-soluble vitamin deficiencies, such as most B vitamins and vitamin C, can occur after weeks or months of malnutrition. Because the body accumulates fat-soluble vitamins (including vitamins A, D, E, K, and B12) in relatively significant quantities, deficiencies of these vitamins may take up to a year to manifest.
Niacin:
Niacin deficiency can cause sunburn, dermatitis, hair loss, and red skin sores. Pellagra skin lesions are symmetrical and appear in sun-exposed areas and at pressure points. The appearance of skin lesions in pellagra might vary, but the homogeneous distribution at the pressure points and sun-exposed areas is more diagnostic. Lesions can form in a glove-like pattern on the hands (pellagrous glove) or a boot-shaped pattern on both legs and feet (pellagrous boot). Sunlight can also create casal necklaces, an erythematous rash in the form of a broad collar, and butterfly-shaped facial lesions.
Vitamin B6:
Vitamin B6 deficiency is characterized by a seborrheic dermatitis-like eruption, angular cheilitis (lip scaling and cracks at the corners of the mouth), atrophic glossitis with ulceration, conjunctivitis, sideroblastic anemia (due to impaired heme synthesis), intertrigo, and neurologic symptoms of somnolence, depression, confusion, and neuropathy.
Vitamin B12:
Vitamin B12 is essential for metabolism, red blood cell synthesis, and nerve function. Megaloblastic anemia, or pernicious anemia, is the primary clinical condition associated with vitamin B12 deficiency. Vitamin B12 insufficiency can cause pallor and brown-gray toenails and fingernail discoloration.
Vitamin A:
Vitamin A is essential for the preservation of epithelial tissues. Follicle hyperkeratosis and widespread xerosis are two dermatological signs of vitamin A insufficiency. Tiny wrinkles and scales characterize vitamin A deficiency-related xeroses. The characteristic feature of follicular hyperkeratosis is reddish-brown follicular papules with a central keratotic spinous plug. These lesions are found at the bony prominences of the elbows and knees, but they can spread further up and down the extremities.
Vitamin C:
Vitamin C functions as a cofactor in various collagen synthesis events and is required for collagen and amino acid production. Dermatologic symptoms of vitamin C deficiency are follicular hyperkeratosis, rough skin, perifollicular hemorrhages, coiled hair, petechiae, easy bruising, and skin tears.
Minerals, Iron Or Zinc:
The human diet must contain nine trace minerals (zinc, molybdenum, selenium, copper, chromium, iron, iodine, manganese, and fluorine) and six micronutrients (sodium, magnesium, potassium, calcium, chloride, and phosphorus).
Iron insufficiency is the most common dietary deficiency worldwide. The body uses iron for various processes, including transporting oxygen to tissues, acting as cytochromes to move electrons inside cells, enabling oxygen storage in muscle, and supporting a wide range of enzymatic reactions in tissues. Some dermatological symptoms of iron deficiency include brittle nails, hair loss, nails with a central groove, pallor, and koilonychia (spoon-shaped nails).
Zinc is found in many enzymes and is necessary for multiple metabolic reactions. Zinc deficiency can manifest as dermatitis, seborrheic dermatitis, xerosis, poor wound healing, and sparse hair.
What are the Skin And Nail Symptoms on the Lower Extremities?
Numerous alterations to the skin and nails may indicate an underlying nutritional deficiency. Identifying symptoms resulting from a nutritional deficiency could help with the diagnosis process and subsequent treatment options.
Pallor:
Pallor is caused by low oxyhemoglobin levels in the skin. It can result from severe anemia, which is linked to a number of dietary deficiencies, such as deficits in iron, zinc, vitamin B12, vitamin B6, and folate.
Dermatitis:
Dermatitis causes itching, edematous, erythematous, vesicular, flaking, weeping, and crusting regions of skin. Dermatitis can be caused by zinc, protein, essential fatty acids, and niacin (vitamin B3) deficiencies.
Seborheic Dermatitis:
Seborrheic dermatitis is an inflammatory skin disorder that leads to flaky and erythema, white to yellowish scales that appear on oily sebaceous gland-rich areas, including the scalp and nasolabial fold. Seborrheic dermatitis may indicate a zinc, biotin, or vitamin B6 deficiency.
Petechiae:
Petechiae are 1 to 2 mm red or purple spots on the skin caused by mild bleeding from ruptured capillary blood vessels. Both vitamin C and niacin (vitamin B3) deficiencies can cause petechiae.
Xerosis. Xerosis is characterized by abnormally dry skin and mucous membranes. Dry, scaling, itchy, and cracking skin are the hallmarks of this disorder. Xerosis can be brought on by deficiencies in zinc and vitamin A.
Nail Color Changes:
Many types of nutritional deficiencies can cause nail plate discoloration. Brown-gray nail discoloration has been linked to vitamin B12 insufficiency. Anemia can cause white nails, while malnutrition with several vitamin and nutritional deficits might be indicated by pink or red nails. Biotin deficiency can also increase the risk of fungal nail infections and nail plate discoloration.
Changes in Nail Shape and Surface:
Nutritional deficiencies may lead to changes in nail plate shape and surface. Inadequate iron, folic acid, or protein can cause a central nail plate ridge. A central nail groove can be caused by iron deficiency. A zinc deficiency results in transverse depressions or grooves called Beau's lines in the fingernails or toenails.
Conclusion
Macronutrient and micronutrient deficiencies cause a wide range of skin and nail abnormalities. Understanding the correlation between these dermatological signs and malnutrition can aid in diagnosis and treatment options.
