Causes of Sudden Hair loss in Women

What are the causes of sudden hair loss in women?

Although genetic hair loss is one of the most common causes of hair loss in women, other causes are frequently seen as well. What differentiates some of these other conditions is their speed of hair loss. Genetic hair loss tends to be a slow type of hair loss, whereas other types of hair loss can be more rapid. 

The 3 most common causes of rapid hair loss are telogen effluvium and alopecia areata and scarring alopecias. 

1. Telogen Effluvium

Telogen effluvium (TE) is not a single entity. Telogen effluvium refers to hair shedding that follows a 'trigger' such as low iron, crash diets, thyroid problems, starting mediations, massive stress. Typically TE develops 2-3 months after a trigger. Any internal illness can also trigger a telogen effluvium

2. Alopecia Areata

Alopecia areata is an autoimmune condition that affects 2 % of the world. Sudden onset of hair shedding is one way that the condition can declare itself prior to the development of circular patches of hair loss. 

3. Scarring Alopecias 

Scarring Alopecias refer to a group of autoimmune conditions that leave behind deposits of scar tissue as they move through the scalp. These pieces of scar tissue, prevent hair from regrowing in the area and therefore lead to permanent hair loss. Some scarring alopecias, especially lichen planopilaris can accounce their presence with sudden hair shedding. Affected patients often have scalp itching, burning or scalp tenderness.

4. Chemotherapy 

It is not a surprise that chemotherapy is also on the list of causes of sudden hair loss. Hair loss occurs in about 65 % of individuals receiving chemotherapy and is largely dependent on the specific drugs received. Hair loss usually starts 3-4 weeks after the chemotherapy is started.

5. Hair breakage from chemicals and styling

Recent highlighting or hair dyeing can sometimes trigger hair shedding especially if bleaching was used or their was an inappropriate mixture of chemicals or an inappropriate duration of application to the scalp. Affected patients notice breakage of small hairs sometimes within hours of leaving the salon. 

6. Allergic contact dermatitis

Application of chemicals to the scalp that cause an allergic reaction can cause sudden hair loss.  A classic example is allergy to hair dyes. What bothers patients more from hair dye allergy is not the hair loss but rather the scalp itching and scalp pain that is often present. 

7. Scalp infections

Scalp infections are not common in adults, but a variety of scalp bacterial virus and fungal infections can trigger shedding and sudden hair loss. 

8. Trichotillomania

Trichotillomania, or the self induced pulling of hair can lead to sudden hair loss. AT times of extreme emotional stress, depression and obsessive compulsive disorders hair pulling can lead to rapid hair loss within a short time. 



Women with sudden hair loss should see a dermatologist for careful review of their history, assessment of the scalp up close and review of blood tests. Further blood tests may be ordered depending on the story. 


Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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