Dermatosis refers to diseases of the integumentary system. The integumentary system is formed by the set of organs that forms the external covering of the body. It protects from many threats such as infection, desiccation, abrasion, chemical assault, and radiation damage. The integumentary system includes the skin, specialized cells and cells that have an immune function.  Skin is a thickened keratinized epithelium made of multiple layers of cells that are largely impervious to water. Whereas, the specialized cells secrete melanin to protect the body from the carcinogenic effects of UV rays. It is also comprised of Sweat glands excreting wastes regulates body temperature are also part of the integumentary system. Somatosensory receptors and nociceptors are important components of this organ system that serve as warning sensors, allowing the body to move away from noxious stimuli. Dermatosis classification includes everything on the surface of the body i.e. skin, nails, and hair. Any condition affecting the skin is termed as dermatosis excluding skin conditions that involve inflammation (that would be dermatitis).

Different layers of skin include the epidermis, the dermis, and the subcutaneous tissue and dermatosis may involve changes in any or all of these skin layers. Theoretically skin is divided into four anatomical compartments  – the first consists of inter-related and mutual structures epidermis, papillary dermis, and superficial vascular plexus, the second is reticular dermis and the deep vascular plexus, the third is pilosebaceous units, the eccrine glands, and in certain anatomical locations, the apocrine glands, and last is the subcutaneous tissue (panniculum). For biopsy samples, the size of the skin is mostly 4 mm punch biopsy and representative of all four compartments and should also include hair follicles. However, a larger biopsy (6 mm punch biopsy), or even an incisional biopsy, might be necessary for panniculitis or cutaneous lymphoproliferative disorders. A superficial biopsy is misleading, producing an erroneous pattern and diagnosis.

Dermatosis of the skin is expressed in the following terms rash, lesion, macule, papule, nodule, plaque, vesicles and bullae, lichenification, and pustules. The most common causes of dermatosis are autoimmune disorders, bacteria such as Staphylococcus aureus and Streptococcus pyogenes can cause skin infections, fungus, genetic susceptibility, and viruses. People with the gene HLA-DR4 have a higher risk of experiencing dermatosis compared to others. The diagnosis needs expert advice and for confirmatory diagnosis, a biopsy is also performed to examine the sample under a microscope. The histological diagnosis of cutaneous inflammatory diseases can be confusing as the immune system within the skin responds to antigenic stimuli in limited ways. Also, many inflammatory diseases do not show specific histological features. In view of this complexity and commonality, histological patterns of recognition are beneficial for the differential diagnosis. It is important to know the microanatomy of the skin and its regional variations, in addition to the basic structural alterations that can occur in different pathological conditions. Changes in the skin can be external or internal. Skin infections or contact with an outside substance such as poison oak can cause skin changes. Internal skin conditions could reflect a disease within the body such as lupus or measles. Treatments for dermatosis are often specific to the underlying condition. The treatments for hair loss related to alopecia areata are understandably not the same as those for acne so guidelines have been laid for the dermatosis-related skin condition. A clinicopathological correlation in the histological evaluation of skin for inflammatory dermatoses plays an important role in achieving the diagnosis.