Medical Dermatology

Fungal infection or Mycosis (plural: Mycoses) is a condition in which fungi pass the resistance barriers of the human or animal body and establish infections. Mycoses can result when the climate is hot and humid, and when people live in crowded conditions. Some fungi reproduce through tiny spores in the air. People inhale those spores or they land on the skin. Therefore, fungal infections often start in the lungs or on the skin.

There are many conditions of or affecting the human integumentary system—the organ system that comprises the entire surface of the body and includes skin, hair, nails, and related muscle and glands.

Alopecia means loss of hair from the head or body. Alopecia includes baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair (trichotillomania) can also produce hair loss. This condition is dubbed “traction alopecia”. Hairstyling routines such as ponytails or braids may also induce hair loss, as can hair relaxer solutions, and hot hair irons. In some cases, alopecia is due to underlying medical conditions, such as iron deficiency.

Herpes simplex is a viral disease caused by both Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). Infection with the herpes virus is categorized into one of several distinct disorders based on the site of infection. Oral herpes, the visible symptoms of which are colloquially called cold sores or fever blisters, infects the face and mouth. Oral herpes is the most common form of infection. Genital herpes, known simply as herpes, is the second most common form of herpes. Other disorders such as herpetic whitlow, herpes gladiatorum, ocular herpes (keratitis), cerebral herpes infection encephalitis, Mollaret’s meningitis, neonatal herpes, and possibly Bell’s palsy are all caused by herpes simplex viruses.

Hyperhidrosis is a medical condition in which a person sweats excessively and unpredictably. People with hyperhidrosis may sweat even when the temperature is cool or when they are at rest.

Itch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex while itch leads to a scratch reflex.

A keloid is a type of scar, which depending on its maturity, is composed of mainly either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1. Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to flesh-coloured or red to dark brown in colour. A keloid scar is benign, non-contagious, and sometimes accompanied by severe itchiness and pain, and changes in texture. In severe cases, it can affect movement of skin.

Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye (see uveal melanoma). Melanoma can occur in any part of the body that contains melanocytes.

Melasma (also known as “Chloasma faciei” or the mask of pregnancy when present in pregnant women) is a tan or dark skin discoloration. Although it can affect anyone, melasma is particularly common in women, especially pregnant women and those who are taking oral or patch contraceptives or hormone replacement therapy (HRT) medications.

Nail diseases are distinct from diseases of the skin. Although nails are a skin appendage, they have their own signs and symptoms which may relate to other medical conditions. Nail conditions that show signs of infection or inflammation require medical assistance and cannot be treated at a beauty parlor. Deformity or disease of the nails may be referred to as onychosis.

Nevus is the medical term for sharply-circumscribed and chronic lesions of the skin. These lesions are commonly named birthmarks and moles.

Perioral dermatitis, a condition related to acne vulgaris, consists of red papules that may appear microvesicular that typically affect the nasolabial folds (around the nostrils), perioral area (around the mouth) or perioccular area (around the eyes). It usually affects women between the ages of 20 and 45. It is not uncommon, and has a tendency to recur in individuals who have had it once.

A wart is generally a small, rough growth, typically on hands and feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts, the most common considered to be mostly harmless. It is possible to get warts from others; they are contagious and usually enter the body in an area of broken skin. They typically disappear after a few months but can last for years and can recur.

Human skin color is primarily due to the presence of melanin in the skin. Skin color ranges from almost black to white with a pinkish tinge due to blood vessels underneath. Variation in natural skin color is mainly due to genetics, although the evolutionary causes are not completely certain. According to scientific studies, natural human skin color diversity is highest in Sub-Saharan African populations, with skin reflectance values ranging from 19 to 46 compared with European and East Asian populations which have skin reflectance values of 62 to 69 and 50 to 59 respectively.

Psoriasis is a chronic immune-mediated disease that appears on the skin. It occurs when the immune system sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. There are five types of psoriasis: plaque, guttate, inverse, pustular and erythrodermic. The most common form, plaque psoriasis, is commonly seen as red and white hues of scaly patches appearing on the top first layer of the epidermis (skin). Some patients, though, have no dermatological symptoms.In plaque psoriasis, skin rapidly accumulates at these sites, which gives it a silvery-white appearance. Plaques frequently occur on the skin of the elbows and knees, but can affect any area, including the scalp, palms of hands and soles of feet, and genitals. In contrast to eczema, psoriasis is more likely to be found on the outer side of the joint.

Breaking out (eruption) of the skin. A rash can be caused by an underlying medical condition, hormonal cycles, allergies, or contact with irritating substances. Treatment depends on the underlying cause of the rash. Medically, a rash is referred to as an exanthem.

Rosacea is a chronic condition characterized by facial erythema (redness). Pimples are sometimes included as part of the definition. Unless it affects the eyes, it is typically a harmless cosmetic condition. Treatment in the form of topical steroids can aggravate the condition. It primarily affects Caucasians of mainly northwestern European descent and has been nicknamed the ‘curse of the Celts’ by some in Britain and Ireland, but can also affect people of other ethnicities. Rosacea affects both sexes, but is almost three times more common in women. It has a peak age of onset between 30 and 60.

A seborrheic keratosis (also known as “Seborrheic verruca,” and “Senile wart” is a noncancerous benign skin growth that originates in keratinocytes. Like liver spots, seborrheic keratoses are seen more often as people age. In fact they are sometimes humorously referred to as the “barnacles of old age”.