White : Diseases of the Skin - Disorders of Hair

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Gary M. White & Neil H. Cox

Diseases of the Skin

28	Disorders of Hair

GENERAL APPROACH TO ALOPECIA

Some basic aspects

The approach to alopecia can be simplified by a few basic questions.

•	Is the hair loss diffuse, localized, or in a ‘patterned’ form (such as the temporal and vertex thinning of male baldness)fi Although some disorders such as alopecia areata may cause diffuse or focal loss, the differential diagnoses for these two patterns are generally distinct.
•	Is there follicular scarring or notfi This is a critical sign diagnostically, as well as prognostically for potential hair regrowth.
•	Is the patient actually describing an awareness of thinning or of actual increased hair fallfi This is often rather difficult to interpret, but, for example, profuse sudden diffuse hair fall may suggest telogen effluvium whereas gradual diffuse thinning would favor androgenetic alopecia or endocrine causes of hair loss.
•	What age and sex is the patientfi For example, hair shaft disorders usually present in early childhood and female hair thinning is common after the menopause.
•	Any general health problems or medicationsfi
•	Family history—may be positive in pediatric conditions such as hair shaft disorders, commonly positive for early-age hair thinning in male pattern baldness, may be positive for autoimmune disorders in alopecia areata, etc.

This general approach may be modified according to clinical circumstances; for example, the approach to an adult female patient with hair loss is summarized below.

Approach to hair loss in a woman

It is very common for a woman to present with the chief complaint of hair loss when there is no obvious hair loss on examination. This is probably because subtle loss is noticeable by the patient even when not obviously different from normal variation (Fig.28.6); the greater cosmetic attention paid to hair, and longer hair styles, presumably lead to a greater awareness of altered hair shedding. Hair loss is in any event a more common complaint in women than in men, because autoimmune disorders (thyroid and lupus erythematosus) and sex hormone changes that affect hair are more common in women (Table 28.1). If the patient is experiencing hair thinning (without completely alopecic areas) without any obvious cause, she should be evaluated along the lines described in Table 28.2. If blood tests for ferritin, DHEAS, free testosterone, thyroid-stimulating hormone (TSH), and ANA are normal, the diagnosis is probably androgenetic alopecia (discussed later).

Fig. 28.6 Hair thinning. That one can see the hair loss in this 40-year-old woman is somewhat atypical. Most women who seek medical attention for thinning hair seem to have a full head of hair. This is because a significant portion of the hair must be lost before the change is clinically apparent.

PRACTICE POINTS

•	If a woman says she is losing hair diffusely, but you can’t detect any abnormality on examination, believe her. She is usually right.
•	In the setting of diffuse hair loss in a woman, the diagnosis of lupus erythematosis is unlikely if no other corresponding signs or symptoms are present; diffuse hair loss tends to be in those with acute systemic disease.

Table 28.1 DIFFERENTIAL DIAGNOSIS OF DIFFUSE, EXTENSIVE, SUBACUTE, AND CHRONIC NON-SCARRING HAIR LOSS IN A WOMAN

Disorder	Comments
Telogen effluvium	For example after pregnancy, after significant weight loss
Androgenetic alopecia	See text
Sex hormone	For example polycystic ovary disease,
abnormality	non-classic late-onset adrenal hyperplasia
Iron deficiency	Even if hemoglobin is maintained
Thyroid disease	Diffuse thinning with fine hair in thyrotoxicosis, coarse hair in hypothyroidism
Connective tissue	For example systemic lupus erythematosus,
disease	dermatomyositis
Alopecia areata	A variant termed acute diffuse and total alopecia of the female scalp
Drug-induced alopecia	See text

Table 28.2 APPROACH TO THE WOMAN WITH HAIR LOSS

Ask:	How long has the hair been falling outfi Is the hair falling out all over or just in certain areasfi Are there totally bald areasfi Have you had any severe stresses on the body (e.g. weight loss, high fever, surgery, delivery)fi Is the scalp normalfi Are hairs falling out or breakingfi What drugs or over-the-counter preparations do you takefi Do you have any history of iron deficiencyfi Do you have any trouble with excessive amounts of facial hairfi Do you have any history of menstrual irregularitiesfi
Examine for:	Scarring or non-scarring (i.e. are the follicular openings still presentfi) Distribution Any complete alopecic areas Any scalp disease, for example redness, infiltration, crusting, scaling (biopsy if needed) Strength of anchorage of remaining hairs
Important blood tests	Ferritin: diffuse alopecia occurs with low iron stores Dehydroepiandrosterone sulfate, free testosterone: screens for endocrine disorder Thyroid-stimulating hormone: screen for thyroid abnormality ANA: screening for lupus erythematosus

Fig. 28.7 Telogen effluvium. Any great stress on the body can reset the hair cycle in a significant portion of the hairs. This results in partial hair shedding 2–3 months after the stressor. A thinning across the frontal hairline is typical. Labor and delivery caused the telogen effluvium in this patient. Rapid weight loss is another common cause.