“Alopecia” means “hair loss” in Latin & medical-speak; when it occurs, patients often come to see us. It’s usually not serious, sometimes it is, and it’s invariably distressing. Even if the loss is minimal, people are afraid they’ll go bald. The list of possibilities is full of obscure ones that only a dermatologist can diagnose, but general clinicians can identify the most common causes.
We examine the head to answer two main questions:
- Is there skin disease of the scalp, or not?
- Is hair being lost Diffusely (all over), or Focally (just one or a few spots)
Causes of Hair Loss
| xxxxxNo Scalp Disease Noted • Telogen Effluvium * • Natural Hair Loss Patterns …….. • Female-Pattern *, ** at start …….. • Male-Pattern * • Alopecia Areata ** • Traction Alopecia ** • 2º Syphilis ** • Trichotillomania ** xxxxxMisc. Rare Causes • Hyperthyroidism * • Vitamin A toxicity * • Iron Deficiency ??? * • Zinc Deficiency * • Thallium Poisoning * • Selenium toxicity * • Cancer Chemotherapy * | xxxxxScalp Involvement is Present • Tinea Capitis (Scalp Ringworm) ** • Seborrheic Dermatitis ** • Cellulitis / Folliculitis ** • Psoriasis ** • Discoid Lupus ** • Numerous conditions which require a ……..Dermatologist’s evaluation ….* usually Diffuse hair loss ….** usually Focal hair loss x . . . . x |
Click link for a few Pictures; then you can toggle back & forth as you read.
NORMAL SCALP (Non-Scarring Hair Loss)
Most patients with hair loss do not have scalp disease. Their skin is completely normal. This is also called “non-scarring alopecia” in contrast to “scarring.”
First Step — We determine if the loss is diffuse or not, looking for focal patches of complete (or nearly-complete) baldness. We ask the patient where they’re losing hair. If it’s all coming from one spot, they can often show us.
Focal Hair Loss
** Alopecia Areata — This shows up as one or more patches of complete baldness surrounded by normal hair. If we look carefully we might see some “exclamation point hairs,” for which the shaft near the skin is narrower than the growing tip. These can pluck out easily, confirming the diagnosis.
Alopecia Areata is an autoimmune disease. It usually occurs by itself, but may be a manifestation of Lupus (SLE). So we inquire about other possible SLE symptoms, and order blood tests for Antinuclear Antibodies (ANA). We also order a Rapid Plasma Reagin (RPR) blood test (for Syphilis).
A positive RPR might mean patchy hair loss due to 2° Syphilis, but might be a false-positive common in SLE. A “confirmatory test” is done routinely with the RPR to determine if it’s truly Syphilis, or a false-positive. However, if a person ever had syphilis treated in the past, the “confirmatory” will remain positive forever from that one episode. False-positives RPR values (titers) are usually low (≤1:8); with 2° Syphilis they’re usually lots higher, but it could be hard to distinguish (see link for stages of Syphilis).
We treat Alopecia Areata by injecting the area with steroids. If it’s due to SLE (suspect if a very high ANA), we’d want a Rheumatologist to manage full treatment. Focal hair loss can rarely advance to Alopecia Totalis (complete baldness), or more rarely even Alopecia Universalis (loss of all body hair).
** Secondary Syphilis — This stage of the infection begins around 2-3 months after sexual contact, and can last for 1-2 years. There are many symptoms and manifestations, but patchy hair loss is one of them. It resembles Alopecia Areata, but the main difference is that with the latter, there’s virtually complete baldness within each patch. With Secondary Syphilis, each patch still has full hairs scattered within it. Blood tests for syphilis make the diagnosis for sure. See Hair Loss – Some Pictures.
Other conditions cause focal hair in specific areas:
** Male-Pattern Hair Loss, the typical way males lose hair as they age, begins at the temples, mid-forehead, or the very top of the head. A receding hairline might progress, but often won’t. We speak of male-pattern hair loss as focal, in that the entire scalp isn’t affected all at once.
** Traction Alopecia — Hair loss caused by specific styling that requires traction like pulling on hair, including ponytails and others. This is usually evident from exam, as long as we think about it. Treatment means changing one’s hair style; I always apologize when I discuss this, since I don’t like intruding on anybody’s personal sense of beauty. But it’s important to educate as to bare facts, since long-standing traction alopecia can result in permanent hair loss.
Heat and chemicals can break hairs, which patients sometimes incorrectly perceive as hair loss. Education here is the same.
** Trichotillomania — A nervous tic leading persons to twist or yank at their hair. The pattern of loss can be patchy, diffuse, or simply weird. Some sufferers have insight, and endorse the “bad habit.” Others are obliviously unaware, deny, or conceal, which makes diagnosis harder. Patches of hair loss aren’t completely bald (as in Alopecia Areata), and hairs are broken off at different lengths. Hair loss can become permanent. Treatment ranges from education to psychotherapy (a.k.a. cognitive behavioral therapy) to anti-depressant / anti-anxiety medication.
Diffuse Hair Loss
** Telogen Effluvium — This is the most common cause of hair loss. It may involve from 5% to 15% of the head’s hairs. Upon close examination, we clinicians see the patient’s overall hair appears to be thinning. Casual observers rarely notice until over half the hairs are lost. Patients themselves see large quantities of hair falling when they comb or brush, & are scared to death.
The normal activity of each hair follicle progresses through 2 main phases:
- Anagen: Hair strand grows continuously for 3-6 years (about 90% of hairs)
- Telogen: Resting phase lasting 1-6 months (about 10% of hairs)
The hair is shed at the end of Telogen, and Anagen resumes with a new strand. At birth, follicles gradually begin their activity, cycles aren’t synchronized, so Telogen hairs don’t all fall out together. However, various physical or psychological stressors can cause many follicles to suddenly enter Telogen all at once.
Such stressors can include significant illness, surgery, injury, following childbirth, starting / stopping certain medications (in particular for birth control or acne), severe weight loss, and major psychological trauma. I’ve had two friends experienced this upon leaving home. New medications may be another possibility; there’s no good data, but those implicated have included beta-blockers, anticoagulants, retinoids, propylthiouracil, carbamazepine, and some immunizations.
Telogen Effluvium occurs 3 to 6 months after its trigger. It usually begins to resolve within 6-12 months. A chronic form of the condition can persist longer, with ongoing diffuse hair thinning, but not total baldness. This is much less common.
Our diagnosis is made clinically (without tests): Diffuse, non-focal hair loss without any evidence of scalp disease. It’s nice if we can identify an inciting event. Dermatologists have a variety of diagnostic tricks involving pulling out hairs, but I don’t refer patients. I might order a thyroid test (TSH), a complete blood count (CBC), ferritin level (for iron-deficiency), and a Vitamin D level. I’d rule out other possibilities by history.
Even if I can’t pinpoint the trigger, I reassure patients that:
- Most other people aren’t able to notice
- Nobody becomes totally bald; and
- Hair will grow back normally within 6 months. If not, I refer to Dermatology [have never had to]
The main condition mimicking Telogen Effluvium is Female-Pattern Hair Loss.
** Female Pattern Hair Loss — This is normal hair loss that occurs with aging, presumably due to something genetic. It’s not uncommon among Caucasian women. There’s a gradual progression of diffuse hair thinning, that doesn’t advance to baldness as in men. The hairline in front, and the back of the head, are usually less affected. It usually begins after menopause, though not necessarily. See link for pictures of how it may begin.
Female-Pattern hair loss is distinguished primarily from Telogen Effluvium by occurring much more gradually, & without any trigger event several months earlier. Sometimes an episode of the latter makes the age-related hair loss more noticeable. We rule out more focal causes of hair loss mentioned above by their locations. Scalp skin is of course normal.
The main reason we’d refer to dermatology would be for psychological reasons. Women in our society are much more impacted by normal hair loss than men. If hair loss is affecting quality of life, dermatologists begin with a trial of topical minoxidil (Rogaine®). Just be sure it’s applied to scalp (not the hair), and at least 2 hours before bedtime so it dries in time to not spread during sleep (& cause unwanted hair growth elsewhere).
** Other — Rarely will we look for any of the other obscure condition be responsible for diffuse, non-scarring hair loss. Hyperthyroidism almost always include other symptoms. Vitamin A toxicity is caused by too many vitamin pills, not by dietary extremes like excessive carrot juice (a “pro-form” of the vitamin, which can turn the skin orange-color, but won’t damage the liver). Iron deficiency as a cause of hair loss is controversial. Selenium toxicity only occurs from overdose of over-the-counter vitamin products.
We might think of Zinc deficiency in a debilitated patient, or perhaps the elderly without adequate food access, and persons with cirrhosis or chronic pancreatitis. Zinc deficiency can be made worse by some blood pressure medications (diuretics and ACE-Inhibitors). We diagnose by simply giving zinc supplements; testing zinc blood levels is unreliable.
Acute Thallium poisoning causes immediate nausea, vomiting, and diarrhea, and then rapidly progressive hair loss at 2-3 weeks after ingestion. There’s also painful numbness and tingling in the feet that moves up the legs. We’d call a Poison Control Center if suspicious. We mainly encounter it on TV crime shows.
For a patient with hair loss, we often order blood tests like a CBC, TSH, and iron. We usually never find anything, but we know patients are pleased.
Various Cancer Chemotherapies cause anagen hair growth to stop, resulting in rapid massive hair loss. This is obvious to us from the medical history. If this occurs on its own, we’d consider thallium, boron, or arsenic poisoning; we’d then consult Dermatology, local Poison Control, or the police.
SCALP DISEASE PRESENT (Scarring Alopecia)
** Tinea Capitis (Ringworm) — In developed countries, this only occurs in children; we’d be most unlikely to diagnosis it in an adult unless they were immunocompromised. Scalp lesions are roundish or oval, with scaly plaque. Ringworm wherever in the body, itches, and has a “leading edge” — the borders are darker and more prominent. Sometimes black dots can be seen in the empty hair follicles. Lymph nodes may be swollen in the back of the head. Tinea Capitis occasionally appears as a soft, boggy lump covered with exudate (gook); then it’s called a kerion.
** Seborrheic Dermatitis and Psoriasis — Both these conditions involve the hairline, and may continue spreading further on backwards in the scalp. Both are scaly. We distinguish them as follows:
- Seborrheic Dermatitis is greasy / Psoriatic scales are silvery-white
- Seborrheic Dermatitis often descends to the eyebrows & cheeks
- Psoriasis may be found elsewhere, typically extensor side of elbows, knees, heels, and the sacrum (“extensor” means the side that straightens a joint, like back of elbows, front of knees, back of ankles, knuckles)
Although both may be treated with topical steroid preparations, Seborrheic Dermatitis often responds to antifungal creams. Also, anybody with extensive Seborrheic Dermatitis should be tested for HIV.
** Folliculitis / Cellulitis — Bacterial scalp infections can certainly cause hair loss. Folliculitis means infection of the hair follicles, which we recognize by noting a cluster of tiny red spots where hairs grow out from the skin. It often itches. Cellulitis is a superficial infection of the skin: we see a red patch that feels warm to touch. It’s invariably painful, and tender to touch.
We treat both for the most common skin bacteria: Staphylococcus aureus (if a skin infection is spreading rapidly with no sign of pus, we may treat for Strep, requiring a different antibiotic. Nowadays, in many parts of the country, Staph is usually the MRSA strain, resistant to older drugs, but easily treatable. Since many unusual dermatologic conditions resemble Staph to the non-specialist, if not starting to get better within a few days, we stop the antibiotic and refer to Dermatology.
** Discoid Lupus — This is an autoimmune condition that may exist all by itself, or less-commonly be a part of Systemic Lupus (SLE). We’d notice patchy hair loss with reddish, scaly scalp plaques. We can tell it’s not Alopecia Areata or 2° Syphilis, because neither of the latter causes skin changes. If I suspect Discoid Lupus, I usually ask about other symptoms of SLE, draw an ANA blood test, and refer to Dermatology. If the ANA is high (≥1:320), or I suspect SLE from history, I also send to Rheumatology.
** Numerous Conditions Requiring Dermatologic Evaluation — Lots of obscure conditions cause scarring alopecia. When I see hair loss with skin involvement of the scalp, & don’t really think it fits with any of the few above conditions described, I refer to Dermatology. That’s especially so because most of those conditions don’t have effective treatment; in my opinion, anyone with a disfiguring or disabling condition that can’t be treated, even if I can identify it, should usually see a specialist.
If you haven’t clicked the link for Pictures yet, try it now. And that’s it for the various causes of Hair Loss (Alopecia); hope the topic wasn’t too hairy.
See also Hair Loss for the clinician’s condensed thought-process when face-to-face with a patient.