Alopecia areata (partial hair loss)

 Alopecia areata is one of the non-scarring types of hair loss. 

•  Alopecia areata can affect any hair-bearing area. 
•   Alopecia areata  is recurrent. 
•  Although medically benign, AA can cause severe emotional and psychosocial distress in affected patients and their families. 
•  Alopecia areata  affects men and women equally and occur at any age from birth to the late decades of life. 60% of patients present with their first patch under the age of 20. 

         Causes :

•  The true cause of alopecia areata remains unknown. 
•  No known risk factors exist for alopecia areata, except a positive family history. 
•  The exact role of stressful events remains unclear, but they most likely trigger a condition already present in susceptible individuals, rather than acting as the true primary cause. 

       Pathophysiology 

•  The exact pathophysiology of alopecia areata remains unknown. 
•  The most widely accepted hypothesis is that alopecia areata is a T-cell–mediated autoimmune condition that is most likely to occur in genetically predisposed individuals. 

            Symptoms :

•  The Patchy form is the most common form of AA. 
•  The characteristic lesion of AA is commonly a round or oval, totally bald, smooth patch. 
•  Alopecia areata affects the scalp or any hair bearing area on the body. 
•  No epidermal changes are associated with the hair loss. 
•  In the very active phase of the disease, the pull test may be positive at the margins of the patch. 
•  80% of patients have only a single patch, 12.5% have 2 patches, and 7.7% have multiple patches. 
•  More than one area can be affected at once. 
•  Both regrowth in one site and extension of the alopecia on another site may be seen at the same time in the same patient. 
•  Nail dystrophy may be associated with AA. (From 10 to 66%. Of AA cases). 
•  Alopecia areata is categorized by extent of involvement into: 
•  Alopecia Areata: partial loss of scalp hair 
•  Alopecia Totalis: 100% loss of scalp hair 
•  Alopecia Universalis: 100% loss of hair on all hair-bearing areas. 
•  Alopecia areata can be localized if the extension of involvement is less than 50% of the scalp) or Extensive if the extension of involvement is more than 50% of the scalp (less common). 

• Differential diagnosis 
  

•  In trichotillomania and traction alopecia, twisted and broken hairs are frequently evident. 
•  In Tinea capitis, usually, there is an inflammatory component. However, non-inflammatory Tinea capitis may be most difficult to distinguish from AA. Look for the characteristic scaling in Tinea capitis. 
•  In AGA patients usually demonstrate the typical predictable pattern of balding. Shedding is not prominent and the pull test is usually negative 
• Treatment 
• General considerations 
• Treatment is not obligatory because the condition is benign, and spontaneous remissions and recurrences are common. 
•  All local treatments may help the treated areas, but do not prevent further spread of the condition. 
•  While the FDA has never approved any drug for AA, this does not mean that there are no effective treatments. 
•  Any mode of treatment may require long periods of usage, because of the chronic nature of AA. 
•  For patients younger than 10 years therapeutic options include Minoxidil alone or Minoxidil in combination with a mid-potency topical corticosteroid. 
•  Intralesional corticosteroids are avoided and topical immunotherapy is not implemented for patients younger than 10 years. 
•  For patients over 10 years of age with less than 50% scalp hair loss, the first-line therapy for scalp AA is Intralesional corticosteroid injections into the alopecic patches. 
•  Patients over 10 years of age with more than 50% scalp involvement are referred to the dermatologist. 

           Medications 

• 1. Corticosteroids 
•  Corticosteroid therapies can include intralesional injections or topical application. 
•  Topical steroids: 
•  They can especially in children who cannot tolerate injections. 
•  Treatment must be continued for a minimum of 3 months before regrowth can be expected, and maintenance therapy often is necessary. 
•  The most common adverse effect is local folliculitis, which appears after a few weeks of treatment. Also telangiectases and local atrophy also have been reported. 
•  No systemic adverse effects have been reported. 
•  Intralesional steroids (prescribed by physicians) 
•  They are the first-line treatment in localized conditions for adult patients with less than 50% of scalp 
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•  Not suitable for children under 10 years of age owing to the local pain at the injection sites. 
• 2. Minoxidil 
•  The exact mechanism of action of Minoxidil remains unclear. 
•  It must be applied twice daily. 
•  Initial regrowth can be seen within 12 weeks, but continued application is needed to achieve cosmetically acceptable regrowth. 
•  The efficacy of Minoxidil solution can be enhanced with topical corticosteroids. 
•  In combination with topical Minoxidil, topical corticosteroid cream is applied twice daily, 30 minutes after each use of Minoxidil. 
•  Side effects of Minoxidil are rare like local irritation, allergic contact dermatitis, and facial hair growth (Hypertrichosis) which tends to diminish with continued treatment. 
•  Systemic absorption is minimal. 
•  Minoxidil was of little benefit in patients with alopecia totalis or alopecia universalis. 
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• 3. Counter-irritants 
•  They cause blisters and erythema, and an immunologic patient response to modify the perifollicular immunologic milieu. 
• Prevention 
• · Alopecia Areata is highly unpredictable. 
• · No treatment is effective in preventing or stopping the progression of the condition. 
• · No trigger can be found to explain disease exacerbation in most patient. 

             Patient Education 

•  Patient education is a key factor in alopecia areata. 
•  Reassure patients that the condition is benign and does not threaten their general health. 
•  Inform patients that expectations regarding therapy should be realistic.Contributor Information and Disclosures 
•  Inform patients of the chronic relapsing nature of alopecia areata. 
•  Most patients try to find an explanation about why this is happening to them. Reassure these patients that they have done nothing wrong and that it is not their fault.