Patchy hair loss caused by skin disease

Patchy hair loss caused by skin disease

Scalp ringwormInflammation, often with pustulation, is a feature of animal ringworm, and the resultant scarring can be severe. The classical scalp ringworm derived from human sources causes areas of scaling with broken hairs.

Psoriasis

The rough removal of adherent scales can also remove hairs, but regrowth is the rule.

Scarring alopecia

Hair follicles can be damaged in many ways. If the follicular openings can no longer be seen with a lens, regrowth of hair cannot be expected.

Sometimes the cause is obvious: a severe burn, trauma, a carbuncle or an episode of inflammatory scalp ringworm. Discoid lupus erythematosus, lichen planus  and morphoea  can also lead to scarring alopecia. The term ‘pseudopelade’ is applied to a slowly progressive non-inflamed type of scarring which leads to irregular areas of hair loss without any apparent preceding skin disease. If inflammation is present, a biopsy may help to estab-lish the diagnosis.