Hair loss can be a distressing experience, significantly impacting an individual's quality of life. While not life-threatening, it can cause considerable psychological distress. Patients often seek help from their family physicians initially, presenting with either diffuse or patchy hair loss. Understanding the various causes of hair loss and appropriate treatment options is essential for effective management.
Hair growth occurs in three phases:
Disruptions in these phases can lead to different types of hair loss.
A detailed history and physical examination are crucial for determining the cause of hair loss. It is important to differentiate between nonscarring (noncicatricial) alopecia, which is usually reversible, and scarring (cicatricial) alopecia, which is permanent. Scarring alopecia is rare and may be associated with autoimmune diseases like discoid lupus erythematosus. If follicular orifices are absent, scarring alopecia is likely, and referral to a dermatologist is recommended.
Hair loss can be broadly categorized into focal (patchy) and diffuse etiologies.
Read also: The Link Between Seborrheic Dermatitis and Hair Loss
Patchy hair loss is characterized by hair loss in specific areas of the scalp and is often due to conditions such as alopecia areata, tinea capitis, and trichotillomania.
Alopecia areata is an autoimmune disease that results in patchy hair loss. It affects approximately 2% of the population, with no significant difference between sexes. About 20% of affected patients are children. The exact etiology is unknown, but the pathogenesis is likely autoimmune. Patients may experience a single episode or have recurrent episodes.
Evaluation of the scalp may reveal short vellus hairs, yellow or black dots, and broken hair shafts. Microscopic examination may show exclamation mark hairs (hairs that are narrower closer to the scalp).
Tinea capitis is a dermatophyte infection of the hair shaft and follicles, primarily affecting children. The most common cause in North America is Trichophyton tonsurans. Transmission occurs through person-to-person contact or from asymptomatic carriers.
Patients typically present with patchy alopecia with or without scaling, and the entire scalp may be involved. Other findings include adenopathy and pruritus. Children may develop a kerion, a painful, erythematous, boggy plaque, often with purulent drainage and regional lymphadenopathy.
Read also: Is Head & Shoulders Effective for Seborrheic Dermatitis?
If the diagnosis is unclear, a skin scraping from the active border of the inflamed patch can be examined microscopically for hyphae using a potassium hydroxide preparation.
Tinea capitis requires systemic treatment. Options include oral terbinafine, itraconazole, fluconazole, and griseofulvin. Griseofulvin is often preferred for Microsporum species infections.
Trichotillomania is an impulse-control disorder characterized by the compulsive pulling, twisting, or twirling of hair. It typically begins around age 13.
Patients present with frontoparietal patches of alopecia that progress posteriorly and may include the eyelashes and eyebrows. The hair may appear uneven, with twisted or broken hairs.
Diagnosis can be challenging if the patient is not forthcoming about their hair-pulling behavior. Treatment options include cognitive behavior therapy and selective serotonin reuptake inhibitors, although evidence of their effectiveness is limited. Psychiatric referral may be indicated.
Read also: Lasting Hair Graft Results
Diffuse hair loss is characterized by hair loss throughout the scalp and is commonly due to telogen effluvium or anagen effluvium.
Telogen effluvium is a nonscarring, noninflammatory alopecia of sudden onset. It occurs when a large number of hairs enter the telogen phase and fall out three to five months after a physiologic or emotional stressor.
Inciting factors include severe chronic illnesses, pregnancy, surgery, high fever, malnutrition, severe infections, and endocrine disorders.
Patients may notice clumps of hair coming out in the shower or in their hairbrush. Examination typically shows uniform hair thinning.
Telogen effluvium is usually self-limited, resolving within two to six months. Treatment involves eliminating the underlying cause and providing reassurance.
Anagen effluvium is abnormal diffuse hair loss during the anagen phase due to an event that impairs the mitotic or metabolic activity of the hair follicle.
It is commonly associated with chemotherapy, particularly cyclophosphamide, nitrosoureas, and doxorubicin. Other causative medications include tamoxifen, allopurinol, levodopa, and bromocriptine, as well as toxins like bismuth, arsenic, and gold.
Anagen effluvium is usually reversible, with regrowth occurring one to three months after cessation of the offending agent. Permanent alopecia is rare. Physician support is crucial for patients in this situation.
Androgenetic alopecia is the most common form of hair loss in both men and women and is a normal physiologic variant. It is more prevalent in white men, with prevalence increasing with age. Women are also affected, particularly after age 70.
Men typically present with bitemporal thinning, thinning of the frontal and vertex scalp, or complete hair loss with residual hair at the occiput and temporal fringes. Women typically present with diffuse hair thinning of the vertex with sparing of the frontal hairline.
Trichorrhexis nodosa occurs when hairs break secondary to trauma or fragile hair.
Causative traumas include excessive brushing, heat application, tight hairstyles, trichotillomania, and chemical treatments such as bleach, dye, shampoo, perms, or relaxers.
Hairs appear to have white nodes, which are fracture sites along the shaft and cortex that have split into several strands.
Laboratory testing may include a complete blood count, iron studies, copper level, liver function testing, thyroid-stimulating hormone level, and serum and urine amino acid levels.
Seborrheic dermatitis is a common skin condition that primarily affects the scalp, causing scaly patches, inflamed skin, and stubborn dandruff. It may go away without treatment, but in adults, it tends to be a chronic condition.
The exact cause of seborrheic dermatitis isn't clear, but it is believed to be linked to a yeast called Malassezia, which thrives on sebum (oil produced by sebaceous glands).
Symptoms may include:
Due to the numerous potential causes of hair loss, there are no routine tests to evaluate hair loss. However, the pull test can be used to assess active hair shedding.
The examiner grasps 40 to 60 hairs at their base and applies gentle traction. A positive result (more than 10% of hairs pulled out) suggests active hair shedding, indicating telogen effluvium, anagen effluvium, or alopecia areata. A negative test does not exclude these conditions.
Regardless of the specific cause, several general strategies can help manage hair loss:
tags: #dermatitis #and #hair #loss #causes #treatment
