Physical exam findings can be the first clue to an associated nutritional deficiency. The rarer and more obscure the association, the more likely it may be targeted on the exam. In this blog, we will review seven of the most common physical findings, along with other associated clinical clues to help you recognize and remember these deficiencies.

Bitot spots

Vitamin A is a fat-soluble vitamin with several specialized roles in vision, particularly dark adaptation and maintenance of the cornea and conjunctiva. Therefore, patients with vitamin A deficiency may complain of night blindness, while physical examination may reveal Bitot (bee-TOH) spots, which are areas of abnormal squamous metaplasia and keratinization that appear as foamy, whitish plaques on the conjunctiva. Outside of the eye, vitamin A plays an important role in epithelial cell maintenance, with a deficiency leading to follicular hyperkeratosis, characterized by rough, raised follicular papules commonly found on the posterior upper arms and other extensor surfaces. If you see either of these characteristic findings, think of vitamin A deficiency.

Corkscrew hairs

Vitamin C, a water-soluble vitamin, plays an important role in collagen synthesis; thus, deficiency can lead to impaired wound healing, fragile blood vessels, and the characteristic finding of corkscrew hairs. These coiled hairs result from weakened connective tissue surrounding the hair follicle, causing distortion of the hair shaft. As the hair grows, it becomes twisted, producing its characteristic corkscrew appearance. Perifollicular hemorrhages is another classic finding, along with easy bruising, bleeding gums, and poor wound healing.

Koilonychia

Although microcytic anemia is a finding commonly associated with iron deficiency, this mineral deficiency can also cause koilonychia. When combined with esophageal webs and iron-deficiency anemia, these findings form the classic triad of Plummer-Vinson syndrome. While the mechanism of koilonychia is not fully understood, iron deficiency can impair normal nail growth and keratinization. This leads to thinning of the nail plate and soft, brittle nails that develop a characteristic spoon-shaped appearance.

Flag sign

Severe protein malnutrition, particularly kwashiorkor, can lead to the flag sign, which is characterized by impaired hair growth and alternating bands of depigmented hair. The lighter bands correspond to periods of inadequate nutrition and impaired hair pigmentation, whereas periods of improved nutritional intake allow more normally pigmented hair to grow. Repeated periods of malnutrition and improved nutrition therefore produce the characteristic alternating bands of lighter and darker hair referred to as the flag sign. Another characteristic skin finding of kwashiorkor is flaky-paint dermatosis, characterized by hyperpigmented areas of skin that peel or desquamate, exposing lighter or hypopigmented skin underneath. Other classic findings of kwashiorkor include edema, a distended abdomen, and sometimes ascites, related in part to hypoalbuminemia. In contrast, marasmus results from severe overall caloric and nutrient deficiency and is characterized by profound loss of subcutaneous fat and muscle wasting, typically without the prominent edema seen in kwashiorkor.

Bowed legs (genu varum) 

Rickets most commonly results from vitamin D deficiency in children and is characterized by impaired mineralization of growing bone and the growth plates. As the child grows and bears weight on inadequately mineralized bones, the lower extremities can develop deformities, most commonly genu varum (bowlegs), although genu valgum (knock-knees) can also occur. Other findings may include a rachitic rosary characterized by prominent, bead-like enlargement of the costochondral junctions along the chest, frontal bossing with a prominent or protruding forehead due to enlargement of the frontal bones, and widening of the wrists and ankles. In adults, the growth plates are closed, so these characteristic growth-related deformities do not occur. Instead, defective mineralization is termed osteomalacia, which can present with diffuse bone pain, proximal muscle weakness, and an increased risk of insufficiency fractures.

Casal necklace

The classic four D’s of vitamin B3 (niacin) deficiency, or pellagra, are dermatitis, diarrhea, dementia, and, if untreated, death. The dermatitis is characteristically photosensitive, occurring in sun-exposed areas and often becoming hyperpigmented and thickened. When this dermatitis develops in a circumferential distribution around the neck, it produces the characteristic Casal necklace.

Periorificial and acral dermatitis

Zinc deficiency can produce a characteristic acral (distal extremity) and periorificial dermatitis, consisting of erythematous, scaly, or crusted lesions involving the hands, feet, and areas surrounding body openings, particularly the mouth and anus. Other high-yield findings of deficiency include alopecia, diarrhea, impaired wound healing, and altered taste (dysgeusia). This combination of dermatitis, alopecia, and diarrhea is particularly characteristic of severe zinc deficiency and is classically seen in acrodermatitis enteropathica, an inherited disorder of impaired intestinal zinc absorption, although the same clinical findings can also occur with severe acquired nutritional zinc deficiency.

As obesity medicine specialists, you will be on the front lines caring for patients who may have followed restrictive dietary patterns, fad diets, or other practices that increase the risk of nutritional deficiencies. In addition, patients who have undergone malabsorptive procedures are at increased risk for both macronutrient and micronutrient deficiencies. Keep an eye out for these more specific physical examination findings and be familiar with their associated clinical features. Recognizing these clues may earn you a few extra points on exam day and, more importantly, make a meaningful difference in the care of your patients.

Sample Question

An 8-year-old girl is evaluated at a clinic during an international medical mission. Her family has significant financial constraints and limited access to a nutrient-rich diet. On examination, she is thin but does not appear cachectic. Both lower extremities demonstrate outward bowing, similar to what is seen in her younger brother. Which of the following additional physical examination findings is most likely to be present in this patient?

A. Photosensitive rash around the neck
B. Periorificial and acral dermatitis
C. Spoon-shaped nails
D. Perifollicular hemorrhages
E. Bitot spot
F. Rachitic rosary

Next Week: Monthly Knowledge Check: This is a review checklist of must-know items for ABOM exams based on the previous four blog topics. In addition, this will include a brief explanation of the correct answers to previous sample questions.

For more practice questions, check out the following:

  • Obesity Medicine Board Review Questions (2026): Q’s 33, 98, 117, 131, 215, and 265.
  • Obesity Medicine Practice Tests (2026): Q’s 2, 28, 44, 86, 153, 232, 350, and 440.

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