Differential Diagnosis for Exam Finding on the Right Forehead
Single Most Likely Diagnosis
- Alopecia Areata: This condition is characterized by small, round patches of baldness, often with a smooth surface and sometimes accompanied by a few short, broken-off hairs. The presence of a small white round area with balding of the hair on the hairline is highly suggestive of alopecia areata, which is an autoimmune condition that can cause hair loss on the scalp or other parts of the body.
Other Likely Diagnoses
- Tinea Capitis (Ringworm of the Scalp): This fungal infection can cause patches of hair loss, often accompanied by redness, itching, and scaling. The hair loss can be circular and may have a white or grayish appearance due to the fungal infection.
- Pseudopelade of Brocq: A condition that causes scarring hair loss, leading to small, round, smooth bald patches. It's less common than alopecia areata but should be considered in the differential diagnosis for chronic hair loss.
- Discoid Lupus Erythematosus: An autoimmune condition that can cause scarring hair loss, often accompanied by redness, scaling, and inflammation. The lesions can be round and may lead to permanent hair loss if not treated.
Do Not Miss Diagnoses
- Cutaneous Metastasis: Although rare, metastatic cancer to the skin can present as a solitary nodule or patch of hair loss. It's crucial to consider this diagnosis, especially in patients with a known history of cancer, as it requires immediate medical attention.
- Sarcoidosis: A systemic disease that can cause skin lesions, including those on the scalp, leading to hair loss. It's essential to recognize sarcoidosis due to its potential for systemic involvement and the need for specific treatment.
Rare Diagnoses
- Trichotillomania: A psychological condition where individuals compulsively pull out their hair, leading to patches of baldness. The hair loss pattern can be irregular and may not fit the typical round patches seen in other conditions.
- Folliculitis Decalvans: A rare condition characterized by inflammation of the hair follicles, leading to scarring hair loss. It often presents with pus-filled bumps and may require specific antibiotic treatment.
- Kerion: A severe form of tinea capitis that can cause significant inflammation, pus, and scarring hair loss. It's essential to diagnose and treat kerion promptly to prevent long-term hair loss.