Melanoma is the proliferation of atypical melanocytes. It is the most dangerous type of skin cancer. Melanoma has a high potential to invade the dermis and metastasise. 70% of melanoma arises from normal skin, while 30% arise from pre-existing naevi.…
Lichen planus is a chronic, inflammatory, pruritic skin condition. It is characterised by an itchy papular rash commonly on the palms, soles, genitalia, or flexor surface of the arms. It is a T-cell-mediated autoimmune disorder. The diagnosis is clinical. It…
Definition of terms Term Definition Adverse drug reaction (ADR) A noxious and unintended response to medicine that occurs at normal therapeutic doses used in humans for prevention, diagnosis, or therapy of disease, or for the modification of physiologic function Side…
Overview Purines are nitrogen-containing heterocyclic bases that form part of nucleotides. They have a double-ring structure (6-membered ring fused to a 5-membered ring) Precursors for de novo purine ring synthesis Precursor Contribution Glycine C4, C5, N7 Glutamine N3, N9 Aspartate…
Tetrahydrofolate (THF) is essential for purine synthesis and thymidylate (dTMP) formation, both of which are important for DNA synthesis. THF synthesis in Bacteria vs Humans Category Description Bacteria Must synthesize folate de novo Humans Cannot synthesize folate de novo. Folate…
Overview Alopecia means “loss of hair“. Hair grows in small clusters of 3-4 hairs per follicle unit. Hair grows through 3 phases. Follicles can move through this process and back again based on hormonal signalling. Normally, an individual loses about…
Pityriasis versicolor Pityriasis versicolor is a superficial fungal infection caused by Malassezia. It is often asymptomatic, except for the hypopigmented/hyperpigmented patches on the skin. Versicolor means “various colors”. Malassezia produces acetic acid which affects melanocyte function. Diagnosis is clinical, but…
Dermatophyte infections are given different names depending on the location of the infection. The diagnosis is clinical. Deep infections (involving the hair and nails) are treated with oral antifungals. Dermatophytosis Area infected Term Common causative organism Foot Tinea pedis (Athletes…
Overview Common fungal skin infections include: Infection Causative organism Dermatophytosis (Tinea) Dermatophytes – Trichophyton, Epidermophyton, Microsporum Candidiasis Candida spp. Pityriasis versicolor Malassezia furfur, Malassezia globosa
Erythema multiforme is a common reaction pattern of blood vessels in the dermis with secondary epidermal changes. It is an acute, self-limited Type IV hypersensitivity reaction. It manifests as erythematous iris-shaped papular and vesiculo-bullous lesions (Bullseye). The age of onset…
