Raynaud’s phenomenon – Condition in which spasm of arteries cause episodes of reduced blood flow typically in the fingers. Episodes result in the affected part turning white and then blue. Often, there is numbness or pain. As blood flow returns, the area turns red and burns. Episodes are often triggered by cold or emotional stress. There are two main types: primary Raynaud's, when the cause is unknown, and secondary Raynaud's, which occurs due to a connective tissue disorder, such as scleroderma or lupus, injuries to the hands, smoking, thyroid problems, and certain medications, such as birth control pills.Koebner phenomenon – The Koebner phenomenon may result from either a linear exposure or irritation. Conditions demonstrating linear lesions after a linear exposure to a causative agent include: molluscum contagiosum, warts and toxicodendron dermatitis. Warts and molluscum contagiosum lesions can be spread in linear patterns by self-scratching. Toxicodendron dermatitis lesions are often linear from brushing up against the plant. Causes of the Koebner phenomenon that are secondary to scratching rather than an infective or chemical cause include vitiligo, psoriasis, lichen planus.Nikolsky’s signs – The sign is present when slight rubbing of the skin results in exfoliation of the outermost layer. Nikolsky's sign is almost always present in Steven-Johnson syndrome/toxic epidermal necrolysis and Staphylococcal scaled skin syndrome.

Examples of dermatoses:• Acne – When the oil glands in skin cause pimples and scarring• Impetigo – A skin infection caused by bacteria• Melanoma – The most serious form of skin cancer• Moles – Dark growths on the skin• Morphea – Localized scleroderma, or hardened patches of skin• Vitiligo – White of patches of skin• Tinea – Fungal infection of skin that leaves round marks• Nail clubbing – When nails curve around the fingertips due to low oxygen levels in the blood• Onycholysis – When the fingernails become loose and separate from the nail bed• Wrinkles – The influence of aging on skin