There are thousands of possible skin conditions (dermatologists recognize over 3,000), from common to rare/genetic. Here's a comprehensive practical list of major categories and frequently encountered ones, drawn from reliable dermatology sources like DermNet, American Academy of Dermatology (AAD), NIAMS, Mayo Clinic, and others:
INFLAMMATORY & ALLERGIC CONDITIONS
Acne (including acne vulgaris, cystic acne, comedonal acne)
Atopic dermatitis (eczema)
Contact dermatitis (allergic or irritant)
Seborrheic dermatitis
Psoriasis (including plaque, scalp, guttate)
Rosacea
Hives (urticaria)
Angioedema
INFECTIONS
Bacterial: Impetigo, cellulitis, boils (furuncles), folliculitis
Fungal: Ringworm (tinea corporis), athlete's foot (tinea pedis), candidiasis (yeast infections), pityriasis versicolor
Viral: Cold sores (herpes simplex), shingles (herpes zoster), warts, molluscum contagiosum, chickenpox
Parasitic: Scabies, lice
PIGMENTATION & COLOR CHANGES
Hyperpigmentation (e.g., melasma, post-inflammatory hyperpigmentation, dark spots)
Hypopigmentation (e.g., vitiligo)
Acanthosis nigricans (dark, velvety patches, often linked to insulin resistance)
AUTOIMMUNE & BLISTERING DISORDERS
Bullous pemphigoid
Pemphigus
Dermatitis herpetiformis
Lupus erythematosus (cutaneous lupus)
Scleroderma
HAIR & SCALP CONDITIONS
Alopecia areata (patchy hair loss)
Androgenetic alopecia (pattern baldness)
Telogen effluvium (diffuse shedding)
Seborrheic dermatitis of the scalp
GROWTHS, TUMORS & PRECANCEROUS/CANCEROUS
Actinic keratosis (precancerous sun damage)
Basal cell carcinoma
Squamous cell carcinoma
Melanoma
Seborrheic keratosis (benign warty growths)
Cherry angioma
Moles (nevi, some atypical)
OTHER COMMON OR CHRONIC CONDITIONS
Heat rash (miliaria)
Ichthyosis (dry, scaly skin)
Keratosis pilaris (rough, bumpy skin on arms/thighs)
Hidradenitis suppurativa (painful lumps/boils in armpits/groin)
Lichen planus
Prurigo nodularis (itchy nodules)
Urticaria pigmentosa (mastocytosis-related)
ENVIRONMENTAL/TRAUMA-RELATED
Sunburn & photoaging (wrinkles, age spots/liver spots)
Chilblains
Burns/scars
Pressure ulcers (bedsores)
Many can overlap e.g., like acne can lead to dark spots, eczema to infections if scratched...