Hair Loss

In dermatology, hair loss is termed alopecia. This condition may be an isolated problem or associated with a certain scalp disease or scarring. Alopecia can be either localised or diffused. It can affect the scalp or other body parts. Hair loss may be due to poor quality hair, hair shedding, or hair thinning. Some affected areas may be completely bald. Depending on the condition, hair loss may be either a temporary or permanent issue. Any kind of hair loss reduces an individual's quality of life and causes psychosocial problems.

Hair loss affects any individual at any age with any hair type or hair colour. Hair loss can result from multiple causes.

The Hair Growth Cycle

Hair growth follows a cycle. There are three main phases of the hair cycle. Anagen is the first phase during which hair is actively growing. The second phase is catagen. This is an intermediate phase that lasts 2 to 3 weeks during which active growth stops and follicles shrink. Telogen is the resting phase. These three phases are not synchronised, and different hairs may be at different phases of the hair growth cycle.

As hair grows in cycles, the affected cycle often gives a name to a certain hair loss condition.

Causes of Hair Loss

Anagen hair loss is caused by decreased hair growth. Telogen hair loss is caused by an increased proportion of hair in the resting phase with subsequent shedding. Other causes include congenital or acquired abnormalities of the hair shaft, the presence of inflammatory skin disease that can negatively affect the hair bulb, and changes from thick terminal hair to thin vellus hair.

Symptoms and Features

The features of hair loss vary with the cause. Itch and soreness are absent except when hair loss is caused by inflammatory skin disease. Burning and prickling discomfort are common symptoms of hair shedding.

Anagen Hair Loss

Anagen hair loss occurs when hair becomes tapered and/or broken. The duration of the condition varies with each individual. Children can also be affected by anagen hair loss when normal hair is present but cannot grow longer. In adults, anagen shedding occurs with sudden onset. Empty follicles and short broken hairs are common features. Common causes include the presence of autoimmune disease, side effects from medications such as chemotherapy and cytotoxic drugs, and hereditary factors. If anagen hair loss is caused by medications, hair growth may return to normal after 3 to 6 months following discontinuation of those medications.

Telogen Hair Loss

Telogen hair loss refers to excessive hair shedding. The condition becomes visible 2 to 6 months after the event that stopped the active growth of hair. Such events include psychological stress, illness, surgical procedures, fever, weight loss, childbearing, haemorrhage, and medications such as anticonvulsants, anticoagulants, or contraceptives.

Hair Shaft Abnormalities

Hair shaft abnormalities can be inherited and congenital, or caused by disease or injury. In this context, injuries refer to hair bleaching, chemical usage, heat from hair dryers, excessive brushing, and hair pulling. Common features include fractures, irregularities, coiling, and twisting.

Systemic and Dermatological Causes

Hair loss can also be caused by systemic diseases such as syphilis, iron deficiency, or thyroid hormone deficiency. Similarly, hair loss can result from dermatological diseases such as generalised skin disease (erythroderma), localised infection (tinea capitis), or severe skin disease including atopic dermatitis, psoriasis, and cutaneous T-cell lymphoma. These conditions can result in reversible hair thinning, bald patches, and reduced hair quality.

Diagnosis

Hair loss is diagnosed through a full skin examination and patient history. Additional tests may be performed to confirm a diagnosis. For example, a hair pull test may be conducted to assess anagen and telogen hairs. Swabs can be taken to check for the presence of bacterial and viral cultures. Blood tests may be requested for haematology, thyroid function, and serology analysis.

Treatment

Treatment methods for hair loss vary with each patient and are unique to each case. Infections are treated accordingly. Causative medications may be advised to be discontinued. Deficiencies such as iron or thyroid hormone deficiency are addressed as part of the treatment plan.

Prevention

The majority of hair loss conditions cannot be actively prevented. However, certain recommendations can help prevent injuries to the hair shaft:

• Using loose hairstyles to avoid traction injuries.
• Minimising the use of chemical treatments.
• Drying hair naturally or setting the hair dryer to a cool setting to avoid heat damage.