Oral and Mucosal Symptoms
Symptoms of the oral cavity that may arise secondary to EDs and feeding disorders include glossitis, stomatitis, cheilitis, and dental erosions. Mucosal symptoms have been observed in patients with vitamin B deficiencies, inflammatory bowel disease, and other malabsorptive disorders, including patients with EDs.86-88 Patients following restrictive diets, specifically strict vegan diets, without additional supplementation are at risk for developing vitamin B12 deficiency. Because vitamin B12 is stored in the liver, symptoms of deficiency appear when hepatic stores are depleted over the course of several years.89 Insufficient vitamin B12 prevents the proper functioning of methionine synthase, which is required for the conversion of homocysteine to methionine and for the conversion of methyl-tetrahydrofolate to tetrahydrofolate.89 Impairment of this process impedes the synthesis of pyrimidine bases of DNA, disrupting the production of rapidly proliferating cells such as myeloid cells or mucosal lining cells. In cases of glossitis and/or stomatitis due to vitamin B12 deficiency, resolution of lesions was achieved within 4 weeks of daily oral supplementation with vitamin B12 at 2 μg daily.90,91 Iron deficiency, a common finding in EDs, also may contribute to glossitis and angular cheilitis.29 If uncovered, iron deficiency should be corrected by supplementation based on total deficit, age, and sex. Oral supplementation may be done with oral ferrous sulfate (325 mg provides 65 mg elemental iron) or with other iron salts such as ferrous gluconate (325 mg provides 38 mg elemental iron).29 Mucosal symptoms of cheilitis and labial erythema may arise from irritation due to self-induced vomiting.88
Dental erosion refers to loss of tooth structure via a chemical process that does not involve bacteria; in contrast, dental caries refer to tooth damage secondary to bacterial acid production. Patients with EDs who repeatedly self-induce vomiting have persistent introduction of gastric acids into the oral cavity, resulting in dissolution of the tooth enamel, which occurs when teeth are persistently exposed to a pH less than 5.5.92 Feeding disorders also may predispose patients to dental pathology. In a study of 60 pediatric patients, those with rumination syndrome were significantly more likely to have dental erosions than age- and sex-matched healthy controls (23/30 [77%] vs 4/30 [13%][P<.001]). The same study found no difference in the frequency of dental caries between children with and without rumination syndrome.92 These findings suggest that rumination syndrome increases the risk for dental erosions but not dental caries. The distribution of teeth affected by dental erosions may differ between EDs and feeding disorders. Patients with BN are more likely to experience involvement of the palatal surfaces of maxillary teeth, while patients with rumination syndrome had equal involvement of maxillary and mandibular teeth.92
There is limited literature on the role of dentists in the care of patients with EDs and feeding disorders, though existing studies suggest inclusion of a dental care professional in multidisciplinary treatment along with emphasis on education around a home dental care regimen and frequent dental follow-up.76,93,94 Prevention of further damage requires correction of the underlying behaviors and ED.
Other Dermatologic Findings
Russell sign refers to the development of calluses on the dorsal metacarpophalangeal joints of the dominant hand due to self-induced vomiting. Due to its specificity in purging-type EDs, the discovery of Russell sign should greatly increase suspicion for an ED.17 Patients with EDs also are at an increased risk for self-harming and body-focused repetitive behaviors, including skin cutting, superficial burning, onychophagia, and trichotillomania.19 It is important to recognize these signs in patients for whom an ED is suspected. The role of the dermatologist should include careful examination of the skin and documentation of findings that may aid in the diagnosis of an underlying ED.
Final Thoughts
A major limitation of this review is the reliance on small case reports and case series reporting cutaneous manifestations of ED. Controlled studies with larger cohorts are challenging in this population but are needed to substantiate the dermatologic signs commonly associated with EDs. Translational studies may help elucidate the pathomechanisms underlying dermatologic diseases such as lanugo, pruritus, and alopecia in the context of EDs and malnutrition. The known association between thyroid dysfunction and skin disease has been substantiated by clinical and basic science investigation, suggesting a notable role of thyroid hormone and TSH signaling in the skin local environment. Further investigation into nutritional and neuroendocrine regulation of skin health will aid in the diagnosis and treatment of patients impacted by EDs.
The treatment of the underlying ED is key in correcting associated skin disease, which requires interdisciplinary collaboration that addresses the psychological, behavioral, and social components of the condition. Following a diagnosis of ED, assessment should be made of the nutritional rehabilitation required to restore weight and nutritional status. Inpatient treatment may be indicated for patients requiring close monitoring to avoid refeeding syndrome, or those who meet the criteria for extreme AN in the DSM-5 (ie, body mass index <15 kg/m2),1 or demonstrate signs of medical instability or organ failure secondary to malnutrition.62 Long-term recovery for ED patients should focus on behavioral therapy with a multidisciplinary team consisting of a psychiatrist, therapist, dietitian, and primary care provider. Comparative studies in large-scale trials of cognitive behavioral therapy, focal psychodynamic psychotherapy, and specialist supportive clinical management have shown little to no difference in efficacy in treating EDs.75,95,96
Dermatologists may be the first providers to observe sequelae of nutritional and behavioral derangement in patients with EDs. Existing literature on the dermatologic findings of EDs report great heterogeneity of skin signs, with a very limited number of controlled studies available. Each cutaneous symptom described in this review should not be interpreted as an isolated pathology but should be placed in the context of patient predisposing risk factors and the constellation of other skin findings that may be suggestive of disordered eating behavior or other psychiatric illness. The observation of multiple signs and symptoms at the same time, especially of symptoms uncommonly encountered or suggestive of a severe and prolonged imbalance (eg, xanthoderma with vitamin A excess, aphthous stomatitis with vitamin B deficiency), should heighten clinical suspicion for an underlying ED. A clinician’s highest priority should be to resolve life-threatening medical emergencies and address nutritional derangements with the assistance of experts who are well versed in EDs. The patient should undergo workup to rule out organic causes of their nutritional dermatoses. Given the high psychiatric morbidity and mortality of patients with an ED and the demonstrated benefit of early intervention, recognition of cutaneous manifestations of malnutrition and EDs may be paramount to improving outcomes.