The patient
According to her records this 39-year-old woman had normally been fit and well, apart from a mild rise in her blood pressure at the end of her third pregnancy three years ago. She was concerned about the cracking of her nails and was rather embarrassed by them. She was an avid gardener and wondered if the cracking had occurred after clearing out an extensive growth of weeds a few weeks ago.
First instinct
All the nails seem to be cracked and it seemed unlikely that this was a result of her gardening. There was the possibility of something occupational, but closer questioning was not revealing.
A guide I often use is that if a dermatological problem is asymmetrical it is likely to have an external cause (such as contact dermatitis), and if it is symmetrical it has an internal source (such as atopic eczema).
Differential diagnosis
Chronic paronychia is usually the result of nails being frequently immersed in water. Janice admitted that she washed her hands a great deal during the course of her job and so this would certainly put her at risk. In this condition, the nail fold becomes swollen and a gap may develop between the nail fold and nail plate.
As the condition persists, the nail plate becomes adversely affected and horizontal ridging may result. However, while the nail fold did look a little inflamed – suggestive of acute bacterial infection – there did not seem to be any nail changes apart from the crack. There was no nail fold separation either. In fungal infection, it would be highly unlikely to find all nails affected simultaneously.
When eczema affects the region of the posterior nail fold, the nail matrix may become damaged by the inflammatory process. This may result in several ridges appearing in the nail.
The patient's hands appeared free of any dermatitis and so this could be excluded from the differential.
Beau's lines describe a horizontal cracking of the nails, usually symmetrical and in the same place in all the nails. They develop as a result of the nail matrix ceasing to grow and usually occur when there is a significant illness. This seemed the most likely diagnosis in this patient.
Getting on the right track
It was puzzling why the patient had developed Beau's lines, but closer questioning provided the answer. Several weeks earlier she had visited her sister in Canada and suffered a bout of pneumonia requiring a short stay in hospital there. As it had happened abroad, we'd received no information about the incident. Problem solved – the patient was reassured that the nails would grow through normally in the coming weeks.
Dr Mike Wyndham is a GP in Edgware, Middlesex
Cracked nail
