Differential Diagnosis for Hair Loss
Single Most Likely Diagnosis
- Androgenetic Alopecia: This is the most common cause of hair loss, especially in men, but also affects women. It is characterized by a gradual thinning of hair, particularly on the scalp, due to the conversion of testosterone to dihydrotestosterone (DHT), which affects hair follicles.
Other Likely Diagnoses
- Alopecia Areata: An autoimmune condition that leads to patchy hair loss, often on the scalp, but can also affect other areas of the body. Stress and autoimmune diseases can trigger this condition.
- Telogen Effluvium: A condition that causes excessive hair shedding due to a disruption in the normal hair growth cycle. This can be triggered by stress, hormonal changes, or certain medications.
- Tinea Capitis (Ringworm of the Scalp): A fungal infection that causes hair loss, typically in children, but can also affect adults. It is characterized by circular patches of hair loss with redness and scaling.
- Female Pattern Hair Loss: Similar to androgenetic alopecia in men, but with a different pattern of hair loss, typically affecting the crown of the scalp.
Do Not Miss Diagnoses
- Thyroid Disorders: Both hypothyroidism and hyperthyroidism can cause hair loss. Early detection and treatment of thyroid disorders can prevent or reverse hair loss.
- Autoimmune Diseases: Conditions like lupus or rheumatoid arthritis can cause hair loss as part of their symptomatology.
- Cancer and Its Treatment: Certain types of cancer, such as lymphoma, and cancer treatments like chemotherapy and radiation therapy, can lead to significant hair loss.
- Syphilis: A sexually transmitted infection that can cause hair loss in its secondary stage, among other symptoms.
Rare Diagnoses
- Trichotillomania: A psychological disorder characterized by an irresistible urge to pull out one's own hair, leading to noticeable hair loss.
- Loose Anagen Syndrome: A rare condition that affects hair growth, causing hair to be easily pulled out, especially in children.
- Congenital Alopecias: Rare genetic conditions present at birth that affect hair growth.
- Hair Loss Due to Nutritional Deficiencies: Deficiencies in vitamins and minerals like iron, zinc, or biotin can lead to hair loss, though this is less common than other causes.