“Red, raw tongue; red, raw gut.” —Jeghers, New England Journal of Medicine, 1942. In 1942 it was understood that what was happening in the gut was often reflected in the tongue. A red, irritated tongue was thought to mirror a red, irritated gut. This was seen in B-vitamin deficiencies, glossitis and ileitis. Simply correcting the B deficiency resulted in resolution of both glossitis and ileitis! In addition, oral ulcerations due to niacin deficiency could be mirrored in the stomach as gastritis.
This is remarkable to me. Think about it: for some of our “gut” patients, perhaps all that is needed — or primarily needed — is correction of B deficiency!
That said, in my practice rarely do I see a single, severe micronutrient deficiency causing changes to the tongue as they did in 1942. Today it seems that multiple micronutrients are contributing, and it’s not often that the sole issue is insufficient intake. Rather, I see chronic maldigestion, malabsorption, dysbiosis, intestinal permeability, food allergies or sensitivities, all potentially contributing to micronutrient deficiencies that then show up as changes to the tongue. A coating on the tongue can flag us to think about gut (and oral) microbiome imbalances. Thus, expect to see many different clinical conditions with underlying gut/oral involvement causing pathological changes to the tongue. As your patients heal, their tongues will improve, as well; a handy barometer they can track themselves!
Often tongue changes track with nail changes — check out these blogs for details:
Fingernails: A Window Into the Metabolic Soul
Nutrition Physical Exam: Tongue & Nails Suggest Gut Health
The tongue is a skeletal muscle structure that is very active, metabolically. It contains a rich supply of vessels and nerves (including thousands of taste receptors housed inside the fungiform and circumvallate papillae), lymphatics and mucin secretory glands. Squamous epithelium with a rapid rate of turnover covers the tongue. Its heightened metabolic activity makes it ideal as a physical exam tool.
Figure 1. Basic anatomy of the dorsal tongue. (Dermatol Ther. 2013 Jul-Aug;26(4):364-6.)
Figure 2. Fissured tongue. Fissuring has been associated with psoriasis and Sjogren syndrome. Check the fingernails if no psoriasis present — often telltale punctate lesions on the nails will precede the onset of psoriasis/psoriatic arthritis. Keep the tongue (and mouth) clean — the fissured areas are receptacles for bacteria and other inflammation-causing debris. As you successfully resolve the underlying issues, look for favorable changes to the tongue.
Fissuring often presents with geographic tongue in those with psoriasis. One case report noted improvement of tongue with use of biologic therapy for psoriasis.
Nutrient associations may include B12, folate, iron (and possibly B6, niacin, vitamin A). In the same study (references below), lowered levels of lymphocytes and serum IgG were reported in individuals with fissuring.
Figure 3. Coated tongue. Basically, we’re looking at microbial biofilm. But what is the cause? If you’ve ruled out dehydration (a dry, parched appearance) or consumption of foods such as coffee, think about bacterial or yeast dysbiosis, sourced to gut and/or oral microbiome. In this patient we identified a significant presence of candida species in her gut, despite the fairly mild coating. After resolution with initial treatment, the coating (and symptoms) reappeared with consumption of simple carbohydrate foods. Read her full case-including nail changes, lab results, history.
Figure 3a. Coated tongue/thrush. 42 Year old female with type II diabetes, pretreatment. Significant overgrowth of GI candida and dysbiotic bacteria identified. Thrush was a regular issue with this patient, and has responded nicely to a simple, mild, oil of oregano rinse as a part of her overall plan.
Scalloped tongue/macroglossia. A mild presentation of the scalloped tongue (as seen in these images below from my practice) is an extremely common finding in a variety of conditions. Note that the lateral margins of the tongue are scalloped from the pressure of the teeth — you can see the indentations. In my experience, scalloping appears most often associated with the perpetuating interrelated cycle of food allergies or sensitivities, microbial dysbiosis (consider SIBO or lower GI, depending on clinical picture and labs), maldigestion and micronutrient deficiencies. Mechanistically, I believe what I am seeing in these allergic or food sensitive patients is a form of angioedema.
Other causes of scalloped tongue/macroglossia include: Hypothyroidism, amyloidosis — about 15% of cases will present this (accompanied by a smooth, purpuric appearance) — and Down syndrome.
Figure 4. Scalloped tongue/macroglossia. This patient presented with gluten-induced inflammatory arthritis, dysbiosis/intestinal permeability, mild hypothyroidism, B12 deficiency.
Figure 4a: This patient notes that scalloping occurs immediately after ingestion of antigenic foods.
Figure 4b: This patient has eosinophilic esophagitis with multiple, severe IgG4 and IgE food reactions.
Figure 4c: This individual was suffering with IBS/SIBO, blastocystis hominis infection and multiple food sensitivities.
Figure 5. Atrophic glossitis: Note a smooth, glossy appearance (caused by atrophied filiform papillae) with a red or pink background. This is a severe abnormality and often accompanies glossodynia (burning tongue). I do not see this commonly. Chief nutrients to consider here include B12, folate, B6, iron, riboflavin and niacin deficiencies. Effective treatment should include alpha lipoic acid. Iron deficiency may be associated with a pale pink color rather than the red noted here. Consider pernicious anemia, SIBO and hypochlorhydria in these patients. Food allergy/sensitivity will likely be present.
Riboflavin glossitis: Look for magenta coloring
Pellagrous glossitis: Firey red appearance
Vitamin A-associated glossitis: Possible hyperkeratosis appearance, similar to the keratosis pillaris noted on the lateral portion of the upper arms.
Estrogen-associated glossitis may be seen in patients prescribed HRT/OCP. This is suspected to be caused by estrogen-mediated B vitamin depletion.
In my experience, a good B complex is ideal for most cases, covering many possible B-associated etiologies; although in severe B12 deficiency, subcutaneous injections are probably best.
Glossodynia (burning tongue) can accompany any form of glossitis above, or the tongue may appear normal. Glossodynia can also accompany thrush. I worked with a 60-year-old woman with a decades-long history of anorexia who had severe, atrophic glossitis/glossodynia caused by decades-long B12 and iron deficiencies. Always look for and correct all underlying nutrient deficiencies in glossodynia patients, and treatment should include lipoic acid.
Conditions to be especially attentive to: Adherent white or red patches, termed leukoplakia and erythroplakia respectively, have malignant potential and should be biopsied. Squamous cell carcinomas can occur, and may be mistaken for an apthous ulcer. These conditions are most commonly associated with tobacco use.
Remember that nutrient associated tongue changes will often be accompanied by changes to nail growth, and often sourced to GUT issues.
Again, check out these blogs if you’re interested in learning more on this topic:
Fingernails: A Window Into the Metabolic Soul
Nutrition Physical Exam: Tongue & Nails Suggest Gut Health
References (with my notes)
1. Dermatol Ther. 2013 Jul-Aug;26(4):364-6. (Fissures/geographic/psoriasis)
2. Br J Oral Maxillofac Surg. 1987 Dec;25(6):481-7. (Fissures/nutrient & immune associations)
3. J Community Hosp Intern Med Perspect. 2015; 5(1). (Amyloidosis/scalloping)
4. Dermatol Clin. 2003 Jan;21(1):123-34. (Good overview)
5. N Engl J Med 1942; 227(6):221-228. (Great, classic paper on tongue/nutrient diagnosis)
6. Am Fam Physician. 2010 Mar 1;81(5):627-634. (Good overview, free full text)
Thank you Kara! This review of functional tongue diagnosis is packed with valuable information. I’m bookmarking it to “my favorites” for future reference. You have an impressive collection of truly valuable educational blog posts. Thanks for taking the time to create these.
Wonderful and helpful review, as always, Dr. Kara. Your clinical pearls are so helpful! Thank you!
Joe and Sarah, so glad you like the blogs! Examining tongue and nails– so easy to do and so useful. I also want to give a shout-out to Dr. Michael Stone. He’s really put the nutrition physical exam on the map for functional medicine practitioners.
Thanks Dr. Kara, this is particularly interesting to me as someone who has studies Chinese medicine (which makes extensive use of tongue diagnosis) for many years, and is now transitioning into Functional Medicine as well. In my opinion Chinese Medicine and Functional Medicine have a lot of cross-over, even if the language and core theories are different. I’m looking forward to having a big enough number of FM case histories to start looking at correlations between tongue, pulse (another key diagnostic tool in CM), and Functional lab tests. For example, in CM the sides of the tongue generally represent the liver and gallbladder, and although the notions of the organs are significantly different across the paradigms, there are some significant crossovers too. So will I find that those with impaired liver detox pathways tend to have particular presentations on the lateral edges? Will those with mitochondrial impairment or hypothyroid issues tend to have the typical ‘Yang deficiency’ tongue (pale, ‘puffy’, with scalloped edges)? I’m excited about the insights these comparisons might bring, and how they may inform both disciplines.
Tom, thank you for that reply. I’m so excited that you will are observing for parallels between these two systems. I have high regard for Chinese medicine and am interested in TCM tongue diagnostics- Please keep me posted as you do this work
I certainly will, thanks Dr. K!
HI Tom – We should chat more about this. Invivo was interested in doing some workshops next year on integration of TCM theory into FM. I was interested in teaching clinicians about tongue diagnosis as a good primary tool in assessment. I was also talking to James Thirlwall about being involved too. Give me a call when you have some time,
Great work Kara as usual. Enjoying the interviews. Posting them on the Invivo Clinical facebook page….
Hope to see you next year.