Dermatologic Diseases
Dermatologic diseases are conditions of the skin, hair or nails, spanning inflammation, infection, autoimmunity, genetic disorders and cancer.
Key points
- A useful skin description includes lesion type, colour, border, scale, distribution, symptoms and speed of change.
- Fungal infection, eczema, psoriasis and medicine rashes can resemble one another but respond differently to corticosteroids.
- Rapid progression, mucosal involvement, systemic illness or a changing pigmented lesion raises the urgency of direct examination.
The listings below span unrelated diagnoses and should not be selected from appearance alone; clinical or dermatology assessment guides treatment.
How skin diagnoses are narrowed
Clinicians combine morphology with exposure, medicine, travel, occupational and family history. Dermoscopy, skin scraping, culture, patch testing or biopsy is used when it can distinguish important alternatives. Photographs showing evolution can be more helpful than a single late-stage image.
Matching treatment to mechanism
Emollients restore barrier, antimicrobials target specified organisms and anti-inflammatory medicines suppress immune activity. Using a potent steroid on an unrecognised infection can obscure and worsen it, while unnecessary antibiotics add resistance and allergy risk. Site and skin thickness affect topical absorption.
When to seek urgent care
Seek urgent care for widespread blistering or peeling, mouth or eye involvement, breathing difficulty, rapidly spreading severe pain or redness, fever with a rash or purple spots that do not blanch.