There are five common abnormalities, but you can also suffer ridging, washboard nails, thickening, scarring and loss of nails, all with a variety of causes. Brittleness: increases with age and can be associated with iron deficiency in some people. Roughness: common and usually of little significance. Pits: classical feature of psoriasis, but also found in eczema and in alopecia areata. Onycholysis: Lifting of the nail from the underlying nail bed, which can be found in psoriasis, fungal infections, overactive thyroid, lesions under the nail, associated with some medications, but sometimes without cause. Discoloration: white marks are common and normal. However, coloured nails can often suggest other issues: white nails can be found in liver disease pale nails in anaemia yellow nails in fungal infections green-blue ones in pseudomonas infection black-brown with bruising, moles or melanoma.