presentation and diagnosis of female pattern hair loss

Last reviewed 01/2018

• clinical features:
  • most women present with a history of gradual thinning of scalp hair, often over a period of several years (1,2)
    • hair loss can start at any time between early teens and late middle age
    • frequently a history of excessive hair shedding, but unlike telogen effluvium, hair thinning is usually noticed from the outset
    • pattern of hair loss
      • examination of the scalp shows a widening of the central parting with a diffuse reduction in hair density affecting mainly the frontal scalp and crown
        • in some women the hair loss may affect a quite small area of the frontal scalp whereas in others the entire scalp is involved, including the parietal and occipital regions
        • frontal hairline is typically retained
          • although many women develop a minor degree of postpubertal recession at the temples whether or not they have diffuse hair loss
• diagnosis
  • usually straightforward but other causes of diffuse hair loss may need to be excluded, particularly when the hair loss progresses rapidly
    • a detailed history should be obtained in order to detect any aggravating factors or underlying causes. Inquire about:
      • first manifestation and course of hair loss (chronic or intermittent)
      • past medical history - systemic or newly diagnosed diseases within 1 year prior to first signs of hair loss might indicate that the other causes or aggravating factors are responsible for the hair loss e.g.- diffuse effluvium as a result of severe infection, iron deficiency or thyroid dysfunction
      • occasionally, systemic lupus erythematosus can also present in this way
      • family history of androgenic alopecia or any other hair disorders, such as alopecia areata or hirsutism
      • eating habits e.g. - strict vegetarians, crash diets
      • drug history e.g. - pro-androgenic, antithyroid, anti-epiletics, chemotherapeutic agents
      • gynaecological/obstetric history - age of menarche and menstrual pattern, use of hormonal contraception, pregnancies (successful or unsuccessful), fertility treatment
      • features of androgen excess - excessive facial and/or body hair growth, severe acne, seborrhoea of scalp/skin, menstrual disturbances (2)
      • clinical examination should include examination of
        • hair density - the pattern and distribution of hair thinning
        • scalp skin for, erythema, seborrhoea, scarring or scaling
        • features of hyperandrogenism such as excessive hair growth/hirsutism, signs of severe acne (2)
          
          
    • laboratory investigations is generally unnecessary since diagnosis of androgenetic alopecia is made on clinical grounds
      • however if the history and clinical examination are indicative of androgen excess [e.g. polycystic ovary syndrome (anovulatory cycle, elevated hormonal levels), cycle disturbances, androgen-secreting tumours] (2)
        • perform a free androgen index test [FAI = total testosterone (nmol/ L)) x 100 /sex hormone-binding globulin (SHBG) (nmol/ L))], DHEAS (dehydroepiandrosterone sulphate) and prolactin as screening parameters (2)
          • depending on the results, further endocrinological investigations may be required
            • free testosterone and FAI seem to be sensitive for the detection of hyperandrogenaemia
            • in women, at least 80% of bound serum testosterone is bound to SHBG. Consequently, free serum testosterone levels are substantially influenced by SHBG levels, which limit the interpretation of free serum testosterone
            • the FAI takes this SHBG dependence into account
            • FAI levels of 5 and above are indicative for polycystic ovary syndrome
              • other disorders presenting with clinical and/or biochemical signs of hyperandrogenism such as congenital adrenal hyperplasia, androgen-secreting tumours or Cushing syndrome should be excluded. For this purpose further laboratory testing, e.g. 17-OH-progesterone, follicle-stimulating hormone, oestradiol, prolactin or cortisol may be necessary
        • also consider an androgen-secreting tumour (rare) if rapidly progressive hair loss with oligo- or amenorrhoea and other signs of virilization
      • ferritin level, full blood count, thyroid-stimulating hormone should be considered according to the individual history, especially in diffuse effluvium
    • in difficult cases a biopsy should clarify the diagnosis

Notes (2)

• FAI and hormonal contraception
  • it makes sense to take any hormonal level only on the condition that there is no hormonal intake. Oestrogens lead to elevated SHBG levels, whereas testosterone levels may be only slightly changed. Consequently, the FAI can be markedly improved by hormonal contraception
    • therefore, the minimum pause in hormonal contraception has to be 2 months. The measurements should be taken between 08.00 and 09.00 h, ideally between the second and fifth days of the menstrual cycle
• syphilis is a rare cause of atypical alopecia (2,3) - TPHA/RPR if indicated by clinical differential diagnosis

Reference:

• 1. Sinclair R, Wewerinke M, Jolley D. Treatment of female pattern hair loss with oral antiandrogens. Br. J. Dermatol. 2005; 152: 466-73.
• 2. Blume-Peytavi U et al. S1 guideline for diagnostic evaluation in androgenetic alopecia in men, women and adolescents. Br J Dermatol. 2011;164(1):5-15
• 3. Kennedy C. Syphilis presenting as hair loss. BMJ 1976;2: 854.