Ludwig scale
The standard classification of female pattern hair loss, grades I–III, describing diffuse thinning over the crown with a preserved frontal hairline.
The Ludwig scale is the standard staging system for female pattern hair loss, described in the dermatological literature in the 1970s. It defines three grades of diffuse thinning over the crown and mid-scalp — perceptible widening at the parting (grade I), pronounced thinning with a visibly sparse crown (grade II), and near-total loss over the affected area (grade III) — all with the frontal hairline characteristically preserved. Grading is read on the visible pattern with hair parted centrally — a few seconds that standardise the record.
The scale exists because female pattern loss follows a different geography from male. Instead of the receding line and vertex patch the Norwood scale maps, women typically thin diffusely behind a retained frontal fringe, which is why the two systems are not interchangeable — and why complementary descriptions exist, notably the frontal-accentuation “Christmas tree” pattern described later, and photographic severity scales used in research. The right scale is shorthand; the wrong one obscures the case. Grade is also the language of research eligibility, keeping clinic records compatible with the literature they are compared against.
Staging a female patient carries an obligation staging a male rarely does: the diagnosis behind the grade. Diffuse thinning in women has a broader differential — telogen effluvium, iron deficiency, thyroid disease, endocrine conditions, scarring alopecias — so the grade describes a pattern, not a cause, and a medical workup belongs before any label of pattern loss, let alone before surgery.
For surgical planning the scale frames a harder candidacy conversation. Diffuse thinning often includes the donor region itself, so the androgen-resistant reserve male surgery relies on may be thinner or less dependable; grade, donor trichoscopy and stability over time together decide whether transplantation is a good tool or a poor one for a given woman. A documented grade at every consultation, alongside standardised photographs, is the minimum record for tracking either treatment response or progression.