Alopecia Disease Summary

Last updated: 25 November 2025

Overview

As stated in the Introduction section, alopecia can be localized (patchy) or generalized; it can also be scarring or non-scarring. Scarring alopecia is caused by severe inflammation of the hair follicle resulting in irreversible damage. While non-scarring alopecia is reversible.  

It is discussed in the Epidemiology section that androgenetic alopecia is the most common form of alopecia, affecting both males and females, its prevalence affected by age, gender, and race. In the case of alopecia areata, the lifetime risk of the general population for it is around 2 percent. Other details on its incidence and prevalence are further detailed in this section.

The Pathophysiology section mentions that alopecia areata is an autoimmune condition. While androgenetic alopecia is closely associated with dihydrotestosterone (DHT) production, androgen receptor expression, and 5 alpha-reductase activity. Other details in the processes of these 2 types of alopecia are further discussed in this section.

As mentioned in the Etiology section, the most common causes of alopecia include androgenic or androgenetic alopecia (male and female pattern baldness) and alopecia areata.  

As discussed in the Classification section, non-scarring alopecia can be divided into androgenetic alopecia and alopecia areata. 



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History and Physical Examination

The Clinical Presentation section discusses the pattern of hair loss, the age of onset, and progression of alopecia.

The History section emphasizes the importance of reviewing for medications, severe diet restriction, vitamin A supplementation, thyroid symptoms, concomitant illness, and stress factor in assessing those with alopecia. Just as important is looking at the family history and history of emotional stress or trauma.

The Physical Examination section mentions some of the tests that can be done in alopecia patients such as the hair pull test.

Diagnosis

The Diagnosis and Diagnostic Criteria section discusses the Hamilton-Norwood staging and the Ludwing staging for male pattern hair loss (MPHL) and female pattern hair loss (FPHL) respectively. Also stated in this section is that the diagnosis of alopecia areata is clinical.

The different diagnostic tests that can be done in androgenetic alopecia and alopecia areata are enumerated and discussed in the Laboratory Tests and Ancillaries. As stated in the Imaging section, medical photography can be done in alopecia areata for a baseline examination.  

The Differential Diagnosis section enumerates the conditions that mimic alopecia. 

Management

Ways to assess the severity of hair loss and psychological status in alopecia are discussed in the Evaluation section.

The Pharmacological Therapy section gives details on the different treatment options for alopecia areta and androgenetic alopecia. While the Nonpharmacological section emphasizes the importance of patient education and the value of other interventions such as camouflage cosmetics, hairpieces or scalp prostheses, laser therapy, micropigmentation, and even psychological intervention.

The Surgery section contains details on hair transplantation and scalp reduction.