Purpose of Review
The hair and nails provide valuable clues for physical diagnosis of systemic disease. This review provides an organ system-based framework to categorize hair and nail manifestations of systemic disease, and highlights recent discoveries in the pathobiology of appendageal disease.
Recent Findings
Endocrine disorders such as polycystic ovarian syndrome can present with hirsutism and female pattern hair thinning. Autoimmune thyroid disease is associated with other autoimmune disorders like atopy, alopecia areata, and vitiligo. Cytotoxic chemotherapeutic agents result in anagen or telogen effluvium and nail changes mediated by p53, while molecular-targeted therapies like EGFR inhibitors commonly cause folliculitis and paronychia.
Summary
The hair and nails are appendageal structures of the skin that provide important physical diagnostic clues. Systemic diseases may affect their texture, color, shape, and growth. Physicians should be aware of certain pathognomonic findings that can trigger further diagnostic workup for systemic disease.