Non scarring hair loss, also known as noncicatricial alopecia is the loss of hair without any scarring being present. There is typically little inflammation and irritation, but hair loss is significant. This is in contrast to scarring hair loss during which hair follicles are replaced with scar tissue as a result of inflammation. Hair loss may be spread throughout the scalp (diffuse) or at certain spots (focal). The loss may be sudden or gradual with accompanying stress.
The most common cause is androgenetic alopecia, also known as male pattern or female pattern hair loss due to the effects of dihydrotestosterone (DHT) on the hair follicles. A variety of factors may lead to this condition such as hormonal effects, age, diet, autoimmunity, emotional stress, physical stress, drug effects, genetics, or infections.
Depending on the cause, treatment options include: topical minoxidil, oral finasteride, anti-fungal medications, steroids, hair transplantation, or platelet rich plasma (PRP) therapy. Alternatives for total hair loss include the use of hairpieces or hair fibers.
Signs and Symptoms
Patients will notice either focal or diffuse loss of hair. This may occur due to thinning or shedding of the hair over a sudden or gradual period of time. Stress may be present, and the emotional impact of hair loss is important as it may cause significant distress. Other signs may point to specific causes of the condition. Poor diet may lead to tiredness, other side effects of chemotherapy drugs may be seen, infection can cause itching, stress may lead to pulling of hair or falling of hair. Hair loss may be present in the family, highlighting genetic causes.
Causes
Causes of noncicatricial alopecia can be separated based on focal or diffuse hair loss:
Diffuse:
Androgenetic alopecia: androgenic DHT leads to catagenic miniaturization of hair follicles. Diffuse alopecia areata: diffuse autoimmune destruction of hair follicles Alopecia totalis: unknown but thought to be autoimmune Telogen effluvium: emotional or physiologic stress Anagen effluvium: cancer treatments such as radiation and alkylating agents Dermatopathia pigmentosa reticularis: genetic autosomal dominant condition
Focal:
Alopecia areata: autoimmune destruction of hair follicles
Tinea capitis: fungal infection
Traction alopecia: pulling force applied to hair
Trichotillomania (Trichotillosis)
Diagnosis
There are a number of conditions that may cause non scarring hair loss and the first step is to determine the pattern: focal or diffuse. The next step is to identify if the hair loss is scarring or non scarring. A history and physical examination is necessary as this will provide clues to the ultimate diagnosis. It is essential to ask about the onset, observed pattern, hairstyles, family history, diet, and social history.
Diffuse:
Androgenetic alopecia: history of gradual thinning of hair and characteristic pattern. Males start to lose hair in the front and temples while females lose hair at the top of the head Diffuse alopecia areata: exclamation point hairs Alopecia totalis: concomitant loss of facial and skull hair Telogen effluvium: history of emotional or physiologic stress Anagen effluvium: history cancer treatments such as radiation and alkylating agents Dermatopathia pigmentosa reticularis: genetic autosomal dominant condition
Focal:
Alopecia areata: smooth and round lesions
Tinea capitis: black dots with broken hair strands, may see red, scaly lesions and swollen lymph nodes on the back of head. Traction alopecia: history of tight hairstyles and marginal hairline Trichotillomania: history of pulling hair or evidence of traumatic follicles
Pull Test
This test is performed to estimate the severity of hair loss and refine the differential diagnosis. A clinician grabs sections of hair and observes for active hair loss. A positive pull test is usually caused by telogen effluvium, androgenetic alopecia, and alopecia areata.
Tug Test
A doctor holds the top and bottom of a strand of hair and observes for a break in the middle which may be caused by a hair shaft abnormality.
Card Test
A part in the hair is created and a small card is placed to contrast the color of the hair and visualize thin strands of hair (seen in telogen effluvium) vs short broken strands (seen in hair shaft abnormalities).
Fungal Culture
Scalp is scraped and the specimen is incubated for fungal growth commonly seen in tinea capitis.