Encyclopedia of Health and Medicine

182 The Integumentary System
carefully follow the label directions for the product
and to leave the product on the hair or skin
for the instructed length of time. Most treatment
regimens include combing the hair with a nit
comb after shampooing. All individuals in the
household should receive treatment.
It is also necessary to wash clothing and bed
linens in hot water (130ºF or more) for at least
five minutes, and placing stuffed toys in sealed
plastic bags for two weeks. The hot water wash
kills any lice or nits, and the plastic bag method
deprives any lice or nits that hatch of nourishment.
Because body lice live on the clothing
rather than the skin, washing the clothing in hot
water is usually adequate.
Risk Factors and Preventive Measures
Most pediculosis leaves no residual health consequences,
although secondary infections may
develop with excessive scratching. However, sexual
contact generally transmits pubic pediculosis,
which raises concern for SEXUALLY TRANSMITTED DIS-
EASES (STDS). Body lice (P. humanus corporis) can
carry serious bacterial diseases including typhus.
See also PAPULE; PARASITE; PUBLIC HEALTH CONCERNS
OF INFECTIOUS DISEASES; SCABIES; SEXUALLY TRANSMIT-
TED DISEASE (STD) PREVENTION.
pemphigus An autoimmune disorder in which
large, painful bullae (blisters) form on the SKIN and
mucous membranes. The bullae develop within
the epidermis, the skin’s uppermost layer, giving
them a very thin surface. They rupture and tear
easily, exposing the skin to INFECTION and interfering
with the skin’s ability to carry out its numerous
functions. The ruptured bullae form crusts
while they heal, though typically heal without
scarring. Some forms of pemphigus can cover
large portions of the skin’s surface are potentially
fatal. There are three main forms of pemphigus:
• pemphigus vulgaris, the most common form in
which bullae develop in the MOUTH and under
the eyelids as well as on the skin surfaces of the
face, neck, chest, axillae (underarms), and
groin
• pemphigus foliaceus, the mildest form in which
bullae develop mostly on the skin of the scalp
and face though sometimes involve the back
and chest
• paraneoplastic pemphigus, which occurs only
secondarily to CANCER and can involve the
mucous membrane lining the ESOPHAGUS and
airways (TRACHEA and bronchi)
Pemphigus occurs when antibodies the IMMUNE
SYSTEM produces attack and destroy certain proteins
on the surface of epidermal keratinocytes,
the skin cells that make up the epidermis, causing
them to separate from one another. The proteins
are like glues that hold the keratinocytes together.
Dermatologists do not know what causes pemphigus
to develop as an autoimmune process, though
occasionally it occurs as an ADVERSE REACTION to
certain medications, notably penicillamine (taken
to treat severe RHEUMATOID ARTHRITIS) and carbidopa/levodopa
(taken to treat PARKINSON’S DIS-
EASE).
Symptoms and Diagnostic Path
The primary symptom of pemphigus is the appearance
of bullae that start as small blisters. In early
outbreaks the blisters may rupture and heal without
taking the characteristic bulla form. As outbreaks
become more frequent and progressive,
however, the blisters enlarge over several days to
a week. In the early stages of the disorder’s manifestation,
the pattern and appearance of bullae
may be similar to other autoimmune symptoms,
notably the sores that can appear with HIV/AIDS.
Biopsy of the lesions can help to rule out other
causes.
The location and extent of the bullae characterizes
the form of pemphigus. Pemphigus vulgaris
typically begins with blisters in the mouth, with
outbreaks quickly following on other skin surfaces
as well as the mucous membranes lining the NOSE
and the URETHRA. The bullae of paraneoplastic
pemphigus, which only occurs in conjunction
with cancer, also originate in the mouth though
quickly involve the esophagus as well as the skin.
Pemphigus foliaceus bullae are smaller and remain
confined primarily to the head (scalp and face),
and do not involve the mouth or other mucous
membranes.