A 16-year-old girl presented with non-scaly, discrete areas of hair loss on the scalp. She had a past history of atopic eczema and had a number of depigmented areas on her hands and around her eyes.
What is the most likely diagnosis?
Question 11 A: alopecia areata
C: lupus erythematosus
D: seborrhoeic dermatitis
Correct answer: A Explanation Alopecia areata is an immunologically-based disorder where there are discrete areas of hair loss but without scarring or scaling, and patients with this condition have a higher incidence of atopic eczema, hence A is correct. In lupus erythematosus, there is usually active inflammation with scarring, whereas in trichotillomania there are residual short hairs at the affected site, frequently of the same length, because the patient generally finds it difficult to pull the shorter newly growing hairs. Hypothyroidism can give patchy hair thinning with brittle, straw-like hair and bald patches, along with other symptoms of hypothyroidism (e.g. weight gain, constipation, etc.). Seborrhoeic dermatitis generally gives diffuse scaling on the scalp without hair loss; although it can cause some areas of hair loss, this would be associated with scaling of the scalp.