Onychopathies constitute one of the major challenges faced by a dermatologist in terms of its early detection and diagnosis .

Many disorders can affect the nails, including deformity and dystrophy, infections, and ingrown toenails. Infections can involve any part of the nail and may or may not change the nail's appearance. Most nail infections are fungal (onychomycosis), but bacterial and viral infections occur .

Nails are characteristically affected in skin diseases such as psoriasis (speckling, psoriatic oil spot, crumbling nails, pachyonychia) ,lichen( anonychia, dystrophy) ,alopecia areata (speckling, trachyonychia, longitudinal grooves, leukonychia), atopic dermatitis (shiny nails, transverse grooves, speckling, paronychia) and other diseases.

Nail disorders are assessed by clinical inspection, dermatoscopy , microbiological (including mycological) testing, and histopathological examination by nail biopsy .

Utility of dermoscope as a tool for detection is increasing by the day and its use in onychopathies needs to be explored .

Nail dermoscopy has initially been used for the assessment of nail pigmentation . But its utilization has expanded for the diagnosis of all nail disorders; it became a routine diagnostic instrument, as its reveals helpful information. Dermoscopy can be applied to all visible parts of the nail unit, and even the nail matrix can be studied, in conjunction with intraoperative methods .

Nail dermoscopy offers many advantages. Mostly, it enhances visible nail features; however, it can also help identify additional unique and fascinating features, not visible to the naked eye. It is practical, noninvasive and still opens up a second microscopic level of inspection. It contributes toward confirmation of diagnosis and assessment of treatment response as well as prognosis.

In a cross-sectional study to detect signs of subclinical nail involvement in 68 patients with chronic plaque psoriasis, Forty-six patients showed nail dermoscopic findings. Coarse pits, onycholysis, oil drop sign and splinter hemorrhages were seen .

To the best of the investigator's knowledge, no available studies in the literature evaluate subclinical nail affection in skin diseases as lichen planus, atopic dermatitis and auto immune bullous diseases. Hence, with the help of a dermoscope,early diagnosis and appropriate treatment can be instituted.

Inclusion Criteria:

- Patients complaining of common skin diseases ( psoriasis, atopic dermatitis, alopecia, lichen planus, and bullous diseases)

Exclusion Criteria:

• Patients who had gross visible nail changes will be excluded

patients attending the Dermatology clinic , Assiut University Hospitals, Assiut, Egypt, during a period of one year complaining of ( psoriasis,PRP, lichen planus, atopic dermatitis and auto immune bullous diseases) will be recruited in the study