Ever wondered at the base of the nail what is the half-moon shape light color part of the nail. The Lunula is the light crescent shaped pale color section of the nail that is peeking under the base of nail bed? All of us have lunulae that is dome or crescent shaped white patch or structured at the base of finger nail. This lunulae or the little moon has its own significance in telling us about the health of our body. Our body keeps giving indications of good and bad health or presence of other systemic disease via various factors like lunulae, which are visible to the naked eye. Changes in shape, size and color of lunula is one such health indicator, which tells us about the health of our body. Lunulae with normal shape and size is often seen only in thumb nail and may be absent in other fingers. Absence of lunulae in other finger but thumb nail does not mean individual is suffering with chronic diseases. The published data suggests 5% of healthy elderly individuals do not have any lunulae in all 10 fingers.1
Characteristics of Healthy Lunula Vs. Unhealthy Lunula
One must not monitor shape, size or appearance of lunula daily, if there is no symptom or signs of any illnesses. The published articles also suggest, abnormal lunula in absence of symptoms or signs of diseases may not suggest presence of any acute or chronic illnesses. Abnormal lunulae in presence of symptoms must be further evaluated. It is important to consult physician if you observed abnormal lunulae while suffering with long term symptoms like fever, stomach ache, diarrhea, headache, cough, sneezing, urinary symptoms and constipation. Lunula of a healthy, active and energetic person is clear, white with perfect size and shape that occupies base of nail.
Most individual has normal looking lunula that is half-moon shaped and pale and lies at the base of nail. Many normal healthy individuals may show lunulae only over base of thumb nail and may not show lunulae in other fingers. Few may carry lunulae in thumb, index and middle finger. Absence of lunulae in all fingers including thumb can be a cause of chronic illnesses. But combination of normal thumb lunulae and absence of lunulae in one or four remaining finger may not suggest presence of chronic illnesses.
Following are the description of normal lunula:
- Normal Size- Normal nails appear strong, smooth, and glossy with a normal sized lunula at the base of the nail. The lunula on a normal nail occupies 1/5th of nail surface.
- Normal Appearance- Normal lunula appears clear and pale. Such appearance of lunula suggests normal appearing healthy nail and thus overall good health of an individual.
- Normal Shape Of Lunula- Lunula are crescent or half-moon shape.
- Normal Edge- Healthy lunula has clear and defined edges while lunula in other cases are rough or irregular bordered and intermingled with the nail.
Unhealthy lunula are classified based on change in size, shape and color. Following are the description of dysmophologic features of lunulae described as macrolunula, microlulula and anolumula.2
- Smaller Lunulae (Microlunula)- The normal size of lunula on a fingernail is about 1/5th the size of nail. Smaller lunulae or microlunula are ½ the size or even smaller than normal lunulae. White smaller lunulae are considered abnormal.
- Lunulae Absent (Anolunula)- Absent or small lunula is generally associated with infection like HIV disease3, poor digestion and less immunity. People with such illnesses tend to get tired easily and are generally fatigued.
- Large Lunulae (Macrolunula)- Lunula occasionally is larger in size and may occupy ½ of nail. Such abnormal lunula suggests individual may be suffering with chronic systemic diseases.
- Fading Lunulae- Absent or fading lunula eventually disappears and suggests systemic illnesses
- Lunulae Only Appears On Thumb- The overall health is considered normal, If the lunula only appears on the thumbs. Individual who has lunulae only in thumb must watch for symptoms of chronic illnesses if he is suffering with feeling of low physical energy and feels fatigue.
What Does Absence of Lunula Indicate?
Absence of lunula or anolunula condition indicates following disorder-
- Chronic depression 4
- Chronic renal failure 5
- Patient on dialysis 5
- Metabolic disorder
- Weak digestive system
- Abnormal immune system in the body or
- Repeated multiple gastric infections.
Weak digestive system results in frequent diarrhea and vomiting. Absence of lunulae is observed in individual suffering with chronic inflammatory bowel disease that results in chronic diarrhea. Similarly, endocrinal diseases affecting pancreas, gall bladder and liver enzyme also causes metabolic disorder that results in abnormal lunulae. Absence of lunula also indicates the presence or initiation of chronic renal diseases in the body. However, in few children lunulae is not seen at the time of birth and continues as young child because of congenital anomalies. Occasionally, children as they get older may show slow developing lunulae. Occasionally in few cases little moons disappear suddenly and often the cause is presence of circulatory disorder. The sign of absence of lunulae is a warning sign and reminder for you to consult your primary care physician or specialist as soon as possible.
What Does a Large Lunulae Indicate?
Large lunulae is also known as macrolunulae. Large lunulae are observed in individual suffering with following disease or disorder.6
- Congenital disorder
- Systemic cancer diseases
- Acral fibromyxoma
- Cardiac ischemia
Frequent Application of Cortisone Ointment
As per the literature, little larger shape than normal macro-lunulae or large moon shaped pale lunulae that is located at the base of the finger nail and the thumb may not suggest presence of any diseases. However, the presence of an abnormally big lunulae covering the entire finger or the appearance of white finger nail indicates individual is suffering with chronic disorder like hyperthyroidism, cancer, scleroderma and digestive tract disorder. Disorder of digestive system resulting in macro-lunula often suggest inflammatory bowel disease, hyperacidity and gastrointestinal metabolic disorders. Occasionally individual suffering with systemic liver disease shows the signs of macro-lunulae that covers entire finger nail with a little pink patch on the top. If you notice or observed a macro-lunula of your finger then you must consult primary care physician or specialist for further evaluation to rule out, cardiac and gastric disease, as well as hyperthyroidism and cancer.
What Does a Small Lunulae Indicate?
People with barely visible lunulae also tend to have certain systemic diseases and should consult physician if suffering with chronic symptoms. Early diagnosis and evaluation of chronic illnesses may prevent harmful effects on your health. The causes of small lunulae is same as absence of lunulae. The published data suggests changes in shape of lunulae that results in small size lunulae is frequently seen in individual suffering with connective tissue disorder, metabolic disorder and inflammatory bowel disease. So, it is really necessary for you to consult your physician to rule out any systemic disease by taking the necessary diagnostic tests; and if there is a systemic disease, getting treatment for this underlying disease is very important. But most clinician look for following diseases or disorder when small tiny lunulae are observed.
- Weak Immune System- Small lunulae in individual suffering with frequent upper respiratory or urinary infection suggests possible weak immune system and further investigation is necessary to rule out any abnormal immune disease.
- Metabolic Disorder- Small lunulae is observed in individual suffering with metabolic disorder involving poor metabolism that results in frequent acidosis, lack of iron and B12 vitamin deficiency.
- Hypotension- Small lunulae, which can be barely seen behind the cuticle may be associated with low blood pressure and circulatory disorders.
- Hyperglycemia and Diabetes- Individual suffering with diabetes often shows the sign of small lunulae and position of lunulae may be separated from base of the nail. In few cases well demarcated lines are observed over tiny lunulae. People with small lunulae also tend to develop diabetes faster than people with normal nails and lunulae.
What Does Abnormal Shape of Lunulae Indicate?
We discussed effects of diseases resulting in change of size of lunulae. Similarly, chronic diseases also affect the shape of the lunulae. Examination of nail in individual suffering with chronic disease has shown different shape of lunulae like triangular, circular and irregular shape. Chronic diseases like metabolic disorder, gastrointestinal diseases, renal diseases and thyroid disease can affect shape and size of lunulae.
Abnormal Shape of Lunulae-
- Triangular shape
- Square shape
- Irregular oval or round shape
- Causes of Abnormal Shape of Lunulae.
Hereditary Disorders: Following hereditary disorders shows the change in shape of lunulae:
Injury to Nail or Nail Bed: Nail trauma of any kind is one of the other reasons, which can result in change in the shape of lunulae.
- Chronic Renal Disease
- Lymphatic disease
- Inflammatory bowel disease
Significance of Abnormal Lunulae on the Little Finger-
Lunulae on the little finger is generally not visible under normal circumstances. Presence of lunulae at the base of nail of little finger may not be of any significance. But abnormal shape and size of lunulae over nail of little finger has same medical significance as described above. Abnormal lunulae of little finger often suggests presence of chronic disease related to kidneys.
What Does the Change of Color of Lunulae Indicate?
Lunulae has been discolored in individual suffering with connective tissue diseases like Systemic Sclerosis, Lupus Erythematosus (SLE), Dermatomyositis (DM) and Primary Sjogren’s Syndrome. The color changes observed are described as follows:
- White Colored Lunulae- White Lunulae is associated with healthy nails and is considered natural. The Lunulae in this case are generally dome shaped and are comparatively clearer and should be several shades lighter than the skin.
- Ivory Colored Lunulae- Ivory Lunulae is also associated with normal nails and people with such nails are generally energetic, strong and healthy.
- Grey Colored Lunulae- Grey lunulae indicates low energy and such people tend to get tired easily. People with grey lunulae also get anemia faster than people with white or ivory lunulae. Grey lunulae is also associated with the splenomegaly (enlarged spleen). People who have grey colored lunulae generally have some abnormalities in the normal functioning of the spleen, stomach and digestion.
- Pink or Red Colored Lunulae- Pink or red lunulae on the fingernails indicate the decline of visceral functions and people with pink or red colored lunulae tend to get tired very easily. People with pink or red lunulae are more prone to get diabetes, hyperthyroidism and other lung disorders. Red lunula has been observed in individual suffering with systemic lupus erythematosus.7
- Purple Colored Lunulae- Purple colored lunulae are associated with poor blood circulation of heart and brain. The diseases causing coronary artery disease, cerebral arterial diseases and diseases affecting kidney blood vessels causes insufficient blood and oxygen supply to heart, brain and kidney. Such condition is associated with purple colored lunulae.
- Black Colored Lunulae- Black colored lunulae are associated with severe heart diseases, cancer and drug poisoning or heavy metal poisoning. Black lunulae are very uncommon and indicates life threatening diseases or condition. People with black lunulae generally have severe systemic diseases.
- Nails and Systemic Disease Martin A. Shearn, MD, Director of Medical Education, Clinical Professor of Medicine, West J Med. 1978 Oct; 129(4): 358–363.
- The lunula. Cohen PR1., J Am Acad Dermatol. 1996 Jun;34(6):943-53; quiz 954-6.
- Anolunula in Fingernails among Patients Infected with HIV Pratik Gahalaut, 1 ,* Nitin Mishra, 1 Sandhya Chauhan, 2 Mir Mubashir Ali, 3 Madhur Kant Rastogi, 1 and Richa Thakur 1, ISRN Dermatol. 2014; 2014: 271230.
- The association between absent lunula and depression in depressive outpatients: a case-control study. Zhou H1, Zhao Y, Yu X, Chen S, Chen D, Wang W, Wang Z, Wu X, Zhang Z., Psychiatry Res. 2013 Jan 30;205(1-2):176-8.
- Nail disorders in patients with chronic renal failure undergoing hemodialysis. Martinez MA1, Gregório CL, Santos VP, Bérgamo RR, Machado Filho CD., An Bras Dermatol. 2010 May-Jun;85(3):318-23.
- Nail changes in connective tissue diseases: a study of 39 cases Imane Elmansour,1,& Soumia Chiheb,1 and Hakima Benchikhi1, Pan Afr Med J. 2014; 18: 150.
- Lupus erythematosus-associated red lunula. Wollina U1, Barta U, Uhlemann C, Oelzner P. J Am Acad Dermatol. 1999 Sep;41(3 Pt 1):419-21.