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DERMATOLOGY
Lecture III - COMMON SKIN CONDITIONS AND PATHOLOGY
Hope, by far you must have known a little more about our skin, its functions, its use, its
anatomy and physiology. There is still much to know and much to write about but we
will first make a quick note of some of the common skin conditions and diseases that
come across during routine transcription.
So lets now have a sneak preview of some of the few pathological conditions of the skin.
COMMON SKIN CONDITIONS AND PATHOLOGY
Albinism
Albinism is a genetic and/or hereditary pigment disorder in which melanocytes, cells that
produce chemical called melanin and that are responsible for giving color to the skin, are
present but they do not produce melanin. Characteristics of people with this disorder are
white hair, pale, very light skin and pink eyes. Because of improper melanin formation,
such individuals are very susceptible to skin cancers as skin and melanic act as an
ultraviolet light filter for the body. Though medical science has advanced, but for
albinism there is no medical treatment available still.
Basal cell and squamous cell carcinoma:
Basal cell carcinoma is the most prevalent type of skin malignancy. It arises from the
malignancy of the basal cell layer of the lowest part of epidermis. Excessive exposure to
sun's ultraviolet rays is the most common cause of basal cell carcinoma. It may appear as
a skin sore or firm lump that does not heal. Basal cell carcinoma progress slowly and
hence, is readily curable if detected early. Squamous cell carcinoma originates in the
cells that form the skin's outer surface. It may appear as a scaly or crusty patch that may
develop most often on the rim of the ear, mouth, or scalp. Squamous cell carcinoma can
sometimes also invade nearby organs.
Decubitus ulcers (bed sores, pressure sores)
People who are bedridden, confined to the wheelchair, lacking sensation because of
paralysis, and who cannot or do not change their positions every few hours, their blood
flow is reduced consequent to prolonged pressure. This results in cell death, skin
thickening, consequently leading to blisters and open sores and, finally to skin ulceration
called bedsores or pressure sores. These ulcers occur mostly at places where the bone is
close to the skin, such as heels, ankle, hip, shoulder, elbow, and base of the spine.
Advance bedsores may require debridement to remove dead tissue, whereas in early
stages, they can be treated with special gels or antibiotics.
Eczema
Eczema is an inflammatory skin disease with lesions that may be erythematous, scaly,
blistering, thickened, crusty, oozing, or itchy. These symptoms may exist in combination
or singly. Anti-inflammatories are often prescribed in their treatment. Topical
medications may include coal tar and a cortisone cream, hydrocortisone. If bacterial
infection has set in as a result of scratching, then antibiotics may be prescribed.
Impetigo
Impetigo is a contagious skin infection caused by either staphylococcal or streptococcal
bacteria, characterized by many small, isolated, itchy blisters, some of which may
contain pus. When these blisters break, a characteristic yellow crust forms. Diagnosis can
be made by inspecting the lesions and confirmed by scraping off a sample of cells from
the sores for laboratory exam. Impetigo is most common among in infants and children.
This infection in early stages affects only a small area and hence, can be treated with
topical antibiotic ointments, such as mupirocin (Bactroban). In certain cases, oral
antibiotics like penicillin and cephalosporins may be prescribed.
Kaposi’s sarcoma
Kaposi’s sarcoma is a cancer in which malignant cells appear as red and purple patches
under the skin or mucous membranes. The lesions of Kaposi’s sarcoma originate mostly
on the leg and then may spread to lungs, liver, intestinal tract, or lymph nodes. The skin
lesions themselves are painful. They can be accompanied by swelling, edema, and
low-grade fever.
Melanoma
Melanoma is most lethal form of cancerous growth. It develops when the melanocytes
(pigment cells) undergo malignant changes. Melanoma can frequently metastasize to
other organs such as liver, brain, lungs, and other internal organs. Sunlight exposure is
considered to be a leading contributing factor of this disease. Surgery is the most
effective treatment for this disease. Chemotherapy and radiation therapy are used in
addition to surgery to treat melanoma.
Miliaria
Miliaria, also known as heat rash or prickly heat, is a skin condition characterized by
clusters of tiny blisters filled with perspiration, mostly on the armpits and groin,
sometimes also on chest, waist, and back. These blisters are formed when pores become
blocked and sweat cannot be released from them. The heat rash is itchy. Remedies that
alleviate itching and cool the skin work well for miliaria.
Pruritus
Pruritus is an itching sensation in the skin. It can be caused by a number of local factors
ranging from insect bites, allergic reaction, dry skin, eczema to infectious diseases, or
systemic problems.
Psoriasis
Psoriasis is a chronic skin disorder in which patches of skin become red and covered
with dry silvery scales. The skin makes new cells so fast with psoriasis that they form
silvery scales. The psoriatic patches form initially on the scalp, behind the ears, on the
back of neck, on the elbows and knees, and near the nails of fingers and toes. The cause
of psoriasis is unknown. In some cases, psoriasis is characterized by blisters usually on
palms, and soles and is called pustular psoriasis.
Purpura
Any vascular bleeding disorder characterized by hemorrhage in the tissue, particularly
beneath skin tissue and showing up as bruises, ranging from tiny reddish or purplish
spots called petechia to large hemorrhagic patches called ecchymosis is called purpura.
Most types of vascular bleedings or purpuras are due to temporary change in the blood
composition of platelets or rupturing of blood vessel walls because of deterioration of
tissue making the vessel wall. Several types of purpura are purpura simplex (mostly
hereditary), senile purpura (due to aging), allergic purpura (due to allergy), and
idiopathic cytopenic purpura. Acute idiopathic cytopenic purpura affects children and
follows a viral infection that has a reduced number of platelets, which are instrumental in
blood clotting. Chronic idiopathic thrombocytic purpura affects mostly women in the age
group 20-40 and is an autoimmune disorder in which platelets are destroyed.
Scabies
Scabies is a contagious, intensely itchy and highly infectious parasitic skin disease
caused by itch mite, Sarcoptes scabiei. The mite is most often transferred by direct skin
contact, especially during sexual activity, and less often by indirect contact like sharing
clothing or a towel. The female mite looks for places in skin, which are thickest,
especially at the palms and soles to reproduce. It burrows a tunnel under the skin in
which she deposits her eggs. Larvae hatch within 2 to 4 days. The characteristic itchy
rash is caused perhaps due to hypersensitivity to eggs, or waste products or mites and
larvae. Potent parasite-killer medications like gamma benzene hexachloride and lindane
are used to destroy mites and their eggs. However, nowadays, milder but equally
effective drugs such as permethrin are used.
Skin lesions
Lesions are the pathological conditions resulting from a wound or injury. Primarily, the
skin lesions can be classified into the following
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Macule: A circumscribed lesion of any size, which is flat and discolored and which is
nonpalpable.
Papule: A small, solid, raised skin lesion less than 1 cm in size.
Nodule: Palpable raised skin lesion, 1-2 cm in diameter that is larger than papule
Vesicle: Elevated skin lesion that contains fluid, less than 0.5 cm.
Bulla: Elevated lesion containing fluid greater than 0.5 cm; blisters containing clear
fluid. Pustule: Elevated skin lesion containing pus; abscess.
Tumor: Elevated skin lesion greater than 2 cm in diameter.
Scale: Excessive dry exfoliation from the upper layer of skin.
Wheal: A raised, red lesion, usually accompanied by itching.
Fissure: Small break in epidermis, arack-like sore exposing the dermis.
Ulcer: Lesion caused on the surface of the skin or mucosa caused by superficial loss
of tissues accompanied by inflammation.
Tinea (Ringworm Infection)
Tinea is any fungal skin infection, caused by dermatophytes. The name of the fungus
indicates the body part it affects. The fungi can infect the scalp (Tinea calpitis), the beard
(Tinea barbae), the skin (Tinea corporis), the groin area (Tinea cruris), the feet (Tinea
pedis a.k.a. athlete foot), or fingernails or toenails (Tinea unguium). Tinea infections can
be identified by the distinctive appearance of their lesions. As they most often produce
round lesions, hence, the name ringworm. Most Tinea infections can be treated with
antifungal drugs like clotrimazole, nystatin, and miconazole.
Urticaria (Hives)
Urticaria is an allergic skin disorder, characterized raised pink or pale red lesions with a
flat top. Hives are warm and itchy to touch and normally range in size from one-fourth of
inch to 1-1/2 inch. Hives are most often caused by food allergies. They can also develop
in response to certain drugs, such as penicillin, aspirin, etc; or in response to contact with
insect bites, cats, exposure to detergents or dry cleaning chemicals on clothes. Skin tests
performed by an allergist can help in identifying the substance responsible for hives.
Hives usually disappear on their own within one to seven days. To alleviate the
symptoms, itching, antihistamines, such as diphenhydramine, hydroxyzine, and
cyproheptadine are prescribed. In severe cases, corticosteroids, such as prednisone may
be prescribed.
Vitiligo
Vitiligo is a pigment disorder characterized by area of hypopigmentation, which develop
when melanocytes are damaged. Hypopigmentation may range from small patches to
large sections that cover most of the body. Combination of drug and light therapy is used,
in which a drug is administered and followed by exposure to the ultraviolet light.
This drug is activated by light and stimulates re-pigmentation by increasing the
availability of melanocytes at skin surface. If vitiligo consists of only small, scattered
patches, drugs to stimulate pigmentation may be applied directly to the affected skin and
areas then exposed to the sunlight. In those with vitiligo covering more than half the
body, depigmentation is done by bleaching the rest of the skin.
Warts
Warts are epidermal growths caused by strains of HPV (human papilloma virus), which
infect the epithelial cells of skin and then prompt them to multiply. The virus can spread
abnormally and very fast from one person to another by direct contact. Veruccae vulgaris,
the most prevalent form, develops on fingers, elbows, face and knees. Other types of
warts are filiform, flat, pedunculated, periungual, plantar, venereal, and laryngeal.
Majority of the warts are benign. Warts can be quickly removed by burning them with
electrocautery, laser surgery, cryosurgery, but about one-third may recur.
A many of the common skin pathology has been covered above. So now lets learn about a
few of the common and widely performed skin procedures in the next lecture.
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