Introduction:
The term alopecia refers to hair loss irrespective of the cause and the type. Hair growth consists of three phases.
Growth Phase: Avive growth of hair takes place in this phase which is also called the anagen phase.
Resting Phase: This is the catagen phase where there is no reaction in the hair growth.
Shedding Phase: This is the last phase where the hair is shedding out and is known as the telogen phase.
Typically, an individual sheds around 100 hair daily. Most people do not realize this and get worried. When hair loss occurs, it can be either-
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The condition can be diffused where there is loss of hair occurring from the entire scalp resulting in thinning of hair or thinning of the ponytail in females.
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It can occur in patches at a few places on the scalp.
What Are The Types of Hair Loss (Alopecia)?
Hair loss can be categorized into two major types,
1. Non-scarring.
2. Scarring.
The scarring type can be divided into three types and is also referred to as cicatricial alopecia. It is characterized by a permanent form of hair loss resulting from damage to hair follicles.
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Tinea Capitis:
This type of hair loss is associated with inflammatory changes caused by fungal (ringworm) infection and is contagious in nature. They are associated with bald patches, swelling, severe itching, and red rashes in a ring shape.
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Alopecia Mucinosa:
This condition occurs with the collection of mucinous substances in the hair follicles and the sebaceous glands. The inflammatory response to this accumulation prevents the growth of hair. Initially, the condition can be reversed with early diagnosis and treatment, but when the disease advances the hair follicles are permanently destroyed with scarring.
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Alopecia Neoplastica:
This condition is the result of the metastatic (spread of cancer cells) invasion into hair cells. The infiltration occurs from the breast, lungs, and renal carcinoma (cancer).
Non-scarring alopecia has six major types:
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Telogen Effluvium:
Telogen effluvium is a condition in which excessive loss of hair occurs after some initial event like fever, infection, certain drugs, surgery, or due to stress, which is commonly seen in students during exams. Usually, it recovers after the initial trigger is removed and the patient gets better in 3 months. Sometimes, it can be chronic if constant shedding occurs for more than 6 months and that can be due to iron deficiency, zinc deficiency, and other systemic conditions. For its treatment, the underlying cause should be identified and treated.
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Alopecia Areata:
Alopecia areata is an autoimmune disease where hair loss occurs in patches. It most commonly involves the scalp but can also involve the bearded areas in males. When it affects the entire body, it is called alopecia universalis. It is usually a reversible condition and 80 % of people have regrowth of hair during the first year after hair loss. Topical and oral steroids are the mainstay of treatment, and intralesional steroids can be used in them. Other options for the treatment of alopecia areata are topical irritants like Dimethyl Sulfoxide application or Cantharidine application.
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Androgenetic Alopecia:
Another common hair loss, especially in males, is androgenetic alopecia or male pattern hair loss. It can also occur in females, especially those with hormonal imbalances. For its treatment, camouflage can be used in the form of wigs, synthetic hair, and Minoxidil hair spray is used in this type of alopecia. Oral Finasteride is also used for its treatment.
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Traumatic Alopecia:
Traumatic alopecia involves the voluntary and forceful pulling of the hair from the scalp that is commonly seen in children. Some people suffer from trichotillomania (urge to pull the hair out of the scalp), which comes under traumatic alopecia.
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Tinea Capitis:
The type of Tinea capitis fungal infection can be two types, one is inflammatory and the other one is non-inflammatory. The non-inflammatory type is not associated with scarring.
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Anagen Effluvium:
Anagen effluvium is a type of non-scarring alopecia seen in patients undergoing chemotherapy for cancer management. The anti-cancer drugs are toxic to the growth of hair.
What Are The Other Common Causes Of Hair Loss?
Other causes of hair loss are those in which inflammatory causes permanently destroy the hair follicles like lichen planus, frontal fibrosing alopecia, etc. Other causes of hair loss can be chronic infections, chemotherapy, medications, or hair shaft defects.
One common problem in females is excessive use of hot straighteners and curlers on hair which also weakens the hair shaft and causes excessive loss and shedding of hair.
How To Diagnose Different Types Of Hair Loss?
The cause and the type of hair loss have to be thoroughly evaluated for better treatment planning and to prevent further hair loss.
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The physician may order a blood test to check for thyroid function, blood cell count, auto-antibodies, and certain hormone levels to determine the basic underlying cause of hair loss.
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KOH prep (potassium hydroxide preparation) and culture test are necessary for fungal infection.
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Radiographic investigations in the case of alopecia mucinosa to identify the disease stage.
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Hair biopsy and laboratory analysis will give detailed information on hair loss.
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A hair pull test will be useful to evaluate the strength of the hair strands and the follicular bulb. The test is performed by holding a few hairs from various parts of the scalp and pulling gently. Shedding six or more hairs during the test is a positive sign, indicating active hair loss. The test is generally positive for telogen effluvium, androgenetic alopecia, alopecia areata, and scarring alopecia.
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The images of the hair and scalp lesion can be visualized and recorded through a dermatoscope and this procedure is called dermatoscopy.
Conclusion:
Different types of alopecia have different causes and therefore complete history and physical examination of the patient is necessary for better treatment planning. Checking hair under Wood’s light (long wave ultraviolet light) is preferred to detect any fungal infection in the scalp.
Dermatologists can give optimal and coordinated care to patients with hair loss, especially when the condition is also associated with itching, rashes, and discharges.