Contact dermatitis is an eczematous reaction due to an external agent. This agent can affect the skin by direct contact, by airborne contamination, or by ingestion. Skin changes that occur as a result to exposure to allergenic or irritant substances. Phototoxic dermatitis results when either an allergen or an irritant is activated by sunlight.

Chickenpox (varicella) and shingles (herpes zoster) are distinct diseases caused by the varicella-zoster virus (VZV). The VZV is a herpesvirus. Chickenpox is a highly contagious rash that usually occurs in childhood. It is the manifestation of a primary infection. Shingles is usually a localized, unilateral (occurs on one side of the body) eruption that follows a linear pattern along a nerve.

Dust mite (Dermatophagoides pteronyssinus in Europe and Dermatophagoides farinae in North America), sometimes abbreviated by allergists to HDM, is a cosmopolitan guest in human habitation.

The average life cycle for a male house dust mite is approximately 19–30 days while a mated female house dust mite can live for up to two months, laying eggs for the last 30 days of her life.

Everyone is exposed to ultraviolet (UV) radiation from the sun. Small amounts of UV radiation are beneficial to people, and play an essential role in the production of vitamin D. However, overexposure to UV radiation is responsible for two major public health problems: skin cancer and cataract.Emissions from the sun include light, heat and UV radiation.

Although most of the men do not like to take care of their skin, but it is recommended that at least they should follow some basic steps to make their skin healthy. Skin cell behavior would change automatically with the age. The skin gets thinner, sebaceous glands grow less active, number of blood vessels decreases and skin becomes more fragile. These are the symptoms of skin aging.