The terms eczema and dermatitis are synonymous and denote a polymorphous inflammatory reaction involving the epidermis and dermis. It could be due to various causes and presents a wide range of clinical findings. Acute eczema / dermatitis is characterized by a rapidly evolving itchy red rash (erythema), which may be blistered and swollen. Whereas chronic eczema / dermatitis is characterized by severe itchiness (pruritus), dry scaly skin with an excess production of keratin leading to thickening (hyperkeratosis) and tends to present cracks or fissures. The term “dermatitis” is used more for cases such as irritant or allergic contact dermatitis, caused by external (exogenous) factors that cause skin irritation, while the term “eczema” such as atopic or constitutive eczema is commonly used to denote an internal (endogenous) condition .
Psoriasis, which affects 1.5-2% of the population in the western world, is a chronic autoimmune skin condition with varying clinical forms. It is not caused by an allergy but is attributed to genetic or hereditary predisposition and is not contagious .The most common type is psoriasis vulgaris, otherwise known as plaque psoriasis because of the characteristic plaques formed on the skin. It presents well-defined plaques of red raised skin that can appear on any area of the body, although the knees, elbows, scalp and trunk are the most common locations. The flaky silvery white buildup on top of the plaques is called scale; it is composed of dead skin cells. This scale comes loose and sheds constantly from the plaques. Inflammation and blisters can also occur in some types of psoriasis. The clinical picture varies from a few plaques and can lead to a generalized attack of the skin.
There are three distinct superficial bacterial infections of the outermost layer of the epidermis (stratum corneum) and hair follicles, associated with an overgrowth of natural skin flora on parts of the body where restricted conditions or increased humidity exist: the common skin rash, pitted keratolysis and trichomycosis. The term trichomycosis can be misleading because it implies a fungal infection but the condition is actually due to corynebacteria. It appears with the presence of concretions around the affected hair shafts of the underarm hair (armpit trichomycosis) or the pubic area. The underlying skin is normal. Nappy rash is an example of a nonspecific inflammation of skin folds and is diagnosed only when specific infectious diseases, such as a bacterial rash or candidiasis have been ruled out. Pitted keratolysis is a skin condition that affects the soles of the feet. It more commonly affects those who sweat profusely, clinically known as hyperhidrosis.
Superficial fungal infections are the most common of all mucocutaneous infections of the mucus membranes of the skin often caused by overgrowth of the transitory or permanent skin flora, which is associated with changes in the micro-environment of the skin. Fungi that can cause these infections are classed into three genera: Dermatophytes, Candida and Malassezia furfur. Dermatophytes have the ability to attack any area of hardened epithelium, hair follicles and nails. Candida requires a moist and warm environment, while Malassezia furfur requires a moist micro-environment and lipids for its development.