Alopecia areata is an autoimmune, non-scarring, localised hair loss. In normal conditions, hair follicles are immune-privileged sites. This immune privilege is disrupted in alopecia areata, thereby allowing autoreactive T-cells to target hair follicles. Inflammation disrupts normal hair cycling (hair follicles…
Anagen effluvium is a non-scarring hair loss that occurs when the growth phase (anagen) is disrupted. It is reversible, with hair regrowing 3-6 months after the cause is stopped.
Telogen effluvium is a non-scarring hair loss characterised by a greater proportion of hairs that are in telogen. It commonly occurs after periods of stress (childbirth, blood loss, high fevers and major bone fractures). Hair loss is noted during the…
Actinic keratosis is a dysplastic epidermal lesion that is caused by chronic UV radiation exposure. They appear as rough, scaly patches or papules on sun-exposed skin. They are often the precursor to cutaneous squamous cell carcinoma (cSCC).
Cellulitis is defined as a bacterial infection of the dermis and subcutaneous tissue. It is often caused by a break in the skin, which allows bacteria to enter. It commonly affects the legs and face, though it can infect any…
Folliculitis is a common infection that is defined as inflammation of the hair follicles. It can be due to infections (bacterial or fungal), inflammation, or blockage of the pores. Most cases are superficial. Deeper cases of folliculitis are harder to…
Impetigo is a highly infectious superficial skin infection caused by Staphylococcus aureus and Streptococcus pyogenes. A skin defect usually precedes infection, and this can be in the form of a scratch or abrasion, or a skin condition such as eczema.…
Erythema nodosum is an inflammation of subcutaneous fat that presents as tender, erythematous, nodular lesions. It commonly occurs over the shins, but may occur elswhere e.g., forearms and thighs. It is self-limiting, usually resolving within 6 weeks. The lesions heal…
Eczema herpeticum is a serious, widespread herpes simplex virus (HSV 1 or HSV 2) infection. It affects patients with atopic dermatitis or other skin conditions. In children, it typically presents as an eruption of punched-out ulcers commonly affecting sites of…
Rosacea is a common facial rash. It is characterised by sterile inflammatory papules, pustules, and nodules that may sometimes be mistaken for acne vulgaris, but do not cause comedones. It is associated with the mite Demodex folliculorum, which is a…