Nails in disease. The nails’ color, appearance, shape and nature are taken note of to provide information about the health of a person. They are examined as a routine by all doctors to get some clues about underlying diseases.

Here are some abnormal findings that can help a doctor in his diagnosis:

1. Hygiene. Deposition of dirt under the distal end of nail plate can make a chance for ingestion of pathogens while eating.
   If nail cutting is not done properly it can result in worm troubles in children. Prominent nail can also complicate a skin disease by habitual scratching. Sharp nails in small kids cause small wounds when they do feet kicking or hand waving.
2. Color of the nail.

   a. Nails become pale in anemia.
   b. Opaque white discolouration (leukonychia) is seen in chronic renal failure and nephrotic syndrome.
   c. Whitening is also seen in hypoalbuminaemia as in cirrhosis and kidney disorders.
   d. Drugs like sulpha group, anti malarial and antibiotics ect can produce discolouration in the nails
   e. Fungal infection causes black discoloration.
   f. In pseudomonas infection nails become black or green.
   g. Nail bed infarction occures in vasculitis especially in SLE and polyarteritis.
   h. Red dots are seen in nails due to splinter hemorrhages in subacute bacterial endocarditis, rheumatoid arthritis, trauma, collagen vascular diseases.
   i. Blunt injury produces hemorrhage and causes blue/black discoloration.
   j. Nails become brown in kidney diseases and in decreased adrenal activity.
   k. In Wilsons disease blue color in semicircle appears in the nail.
   l. When the blood supply decreases nail become yellow .In jaundice and psoriasis also nail become yellowish.
   m. In yellow nail syndrome all nails become yellowish with pleural effusion.

3. Shape of the nail.

   a. Clubbing. The nail becomes more convex and the finger tip becomes bulbous and looks like an end of a drumstick. When the condition becomes worse the nail looks like a parrot beak. Consider also the causes of clubbing, congenital injuries, severe chronic cyanosis. Lung diseases like emphysema, bronchiactesis, carcinoma of bronchus and pulmonary tuberculosis.Abdominal diseases like crohn’s disease, polyposis of colon, ulcerative colitis,liver cirrhosisHeart diseases like Fallot’s tetralogy, subacute bacterial endocarditis and etc.
   b. Koilonychia. The nails become concave like a spoon. This condition is seen in iron deficiency anemia. In this condition the nails become thin,soft and brittle. The normal convexity will be replaced by concavity.
   c. Longitudinal ridging is seen in Raynaud’s disease.
   d. Cuticle becomes ragged in dermatomyositis.
   e. Nail fold telangiectasia is a sign in dermatomyositis ,systemic sclerosis and SLE.

4. Structure and consistency.

   a. Fungal infection of nail causes discolouration, deformity, hypertrophy and abnormal brittleness.
   b. Thimble pitting of nail is charecteristic of psoriasis, acute eczema and alopecia aereata.
   c. The inflammation of cuticle or nail fold is called paronychia.
   d. Onycholysis is the separation of nail bed seen in psoriasis,infection and after taking tetracyclines.
   e. Destruction of nail is seen in lichen planus, epidermolysis bullosa.
   f. Missing nail is seen in nail patella syndrome. It is a hereditary disease.
   g. Nails become brittle in raynauds disease and gangrene.
   h. Falling of nail is seen in fungal infection, psoriasis and thyroid diseases

5. Growth. Reduction in blood supply affects the growth of nails. Nail growth is also affected in severe illness. when the disease disappears the growth starts again resulting in formation of transverse ridges.These lines are called Beau’s lines and are helpful to date the onset of illness.