SKIN DISORDERS

Verrucae	Warts. Soft, tan-colored, cauliflower like lesion. Epidermal hyperplasia, hyperkeratosis, koilocytosis. Verruca vulgaris on hands Condyloma acuminatum on genitals (caused by HPV)
Nevocellular nevus	Common mole. Benign.
Urticaria	Hives. Intensely pruritic wheals that form after mast cell degranulation
Ephelis	Freckle. Normal number of melanocytes, ↑ melanin pigment.
Atopic dermatitis(eczema)	Pruritic eruption, commonly in skin flexure. Associated with other Atopic diseases.
Allergic contact dermatitis	Type IV hypersensitivity reaction. Lesions occur at site of contact
Psoriasis	Papules and plaques with silvery scarling, especially on knees and elbows. Achantosis with parakeratotic scaling. ↑ Stratum spinosum, ↓ stratum granulosum. Auspitz sign (bleeding spots when scales are scraped off). Nail pitting, psoriatic arthritis.
Seborrheic keratosis	Flat, greasy , pigmented squamous epithelial proliferation with keratin-filled cyst. Looks “pasted on”. Common benign neoplasm of older persons. Signs of Leser-Trelat=sudden appearance of multiples seborrheic keratoses indicating an underlying malignancy (GI, Lymphoid).
Albinism	Normal melanocytes number with ↓ melanin production due to ↓ tyrosinase activity.
Vitiligo	Irregular areas of complete depigmentation. Caused by ↓melanocytes.
Melasma(chloasma)	Hyperpigmentation associated with pregnancy and OCP use.
Impetigo	Very superficial skin infection. Usually from S. aureus and S. pyogenes. Highly contagious. Honey-colored crusting.
Cellulites	Acute, painful spreading infection of dermis and subcutaneous tissues. Usually from S. pyogenes and S. aureus.
Necrotizing fasciitis	Deeper tissue injury, usually from anaerobic bacteria and S. pyogenes. “Flesh eating bacteria”.
Staphylococcal scalded skin syndrome	Exotoxin destroys keratinocytes attachment in the stratum granulosum only. Fever and generalized erythemotous rash with sloughing of the upper layers of epidermis. Seen in newborns and children..
Hairy leukoplakia	White, painless plaque on the tongue, that can’t be scraped off. EBV mediated. Occur in the HIV (+) patients.