What is the diagnosis for alopecia areata (autoimmune hair loss)?

From the Guidelines

Alopecia areata is diagnosed through a combination of clinical examination and sometimes additional testing, with a focus on the pattern of hair loss and the absence of scarring, as noted in the guidelines for the management of alopecia areata 1. The diagnosis of alopecia areata involves a thorough clinical examination, including a scalp examination for characteristic round or oval patches of hair loss with smooth skin and no scarring.

• A dermatologist may perform a gentle pull test at the edges of the patches to check for active disease.
• Dermoscopy, an examination with a handheld device, may reveal "exclamation point hairs" that are narrower at the base than the tip, which is pathognomonic for alopecia areata, as discussed in the guidelines for the management of alopecia areata 1. In uncertain cases, a scalp biopsy might be necessary, showing lymphocytic infiltration around hair follicles.
• Blood tests may be ordered to rule out other conditions like thyroid disorders or autoimmune diseases that can be associated with alopecia areata, as mentioned in the guidelines for the management of alopecia areata 1. The diagnosis is primarily clinical, based on the pattern of hair loss and the absence of scarring.
• This autoimmune condition causes the body's immune system to attack hair follicles, resulting in the characteristic patchy hair loss, as noted in the guidelines for the management of alopecia areata 1. Early diagnosis allows for prompt treatment, which may include topical or intralesional corticosteroids, topical immunotherapy, or systemic treatments depending on the severity and extent of the condition.
• The choice of treatment depends on the extent and severity of the hair loss, as well as the patient's overall health and preferences, as discussed in the guidelines for the management of alopecia areata 1.

From the Research

Diagnosis of Alopecia Areata

The diagnosis of alopecia areata can be made clinically, with the following characteristics:

• Hairless patches with normal skin and preserved follicular ostia 2
• Exclamation mark hairs and a positive pull test signal activity 2
• Dermoscopy may reveal yellow dots 2
• White hairs may be spared; initial regrowth may also be non-pigmented 2

Clinical Types of Alopecia Areata

Alopecia areata can present in different clinical types, including:

• Patchy AA
• AA reticularis
• Diffuse AA
• AA ophiasis
• AA sisiapho
• Perinevoid AA 2

Differential Diagnosis

The differential diagnosis of alopecia areata includes:

• Trichotillomania
• Scarring alopecia
• Other non-scarring hair loss disorders such as tinea capitis and syphilis 2

Associated Conditions

Alopecia areata may be associated with other conditions, including:

• Atopy
• Autoimmune thyroid disease
• Vitiligo 2
• Nail changes 3

Prognosis

The prognosis of alopecia areata is uncertain and can be influenced by factors such as:

• Subtypes alopecia totalis and alopecia universalis
• Characteristics such as associated nail lesions, hair loss for more than 10 years, and a positive familial history 4
• Early, long-lasting, and severe cases have a less favorable prognosis 2