Vitiligo

Vitiligo is characterized by hypopigmentation of the skin. It is an autoimmune condition that results from melanocyte dysfunction.

Image from Wikimedia Commons.
Available here:http://en.wikipedia.org/wiki/File:Vitiligo2.JPG

Signs and symptoms

-Hypo or depigmented patches that often enlarge and change shape.
-Most prominent on the face, hands and wrists.

Treatment

-UVB phototherapy with or without Psoralen, a material that increases the effect of the UV light. It can be done at home or a few times a week in the clinic.
-Studies have shown that immunomodulators such as topical tacrolimus (Protopic) and pimecrolimus (Elidel) may also cause improvement in some cases, when used with UVB narrowband treatments
-Psoralen and Ultraviolet A light (PUVA) therapy is generally performed in clinic setting.
-Skin camouflage/make up
-Depigmenting with topical drugs like monobenzone, mequinol or hydroquinone may be considered to make the not vitiligous skin appear fairer and uniform. It increases risk of melanoma and consistent sun protection should be advised.

Differential diagnosis

-Pityriasis alba
-Tuberceloid Leprosy
-Post inflammatory hypopigmentation
-Tinea versicolor
-Albinism
-Piebaldism

USMLE pearl: Vitiligo is often associated with other autoimmune diseases including Hashimoto thyroiditis, type I Diabetes Mellitus, Addison's disease, pernicious anemia etc.

Miliaria rubra or prickly heat

Miliaria rubra, or prickly heat is caused by obstruction of sweat ducts in epidermal or dermal layers. This rash is common in infants and children, especially in the summer. It appears over the face, upper trunk, and intertriginous area of the neck, as a result of tight-fitting clothing. Wearing lightweight, loose-fitting clothing, eliminating greasy topical agents, and using corn starch or even talcum powder help get rid of the rash.

Melanomas

When to suspect malignant change in a mole? Look for the following 5 changes (ABCDE):

Asymmetric shape

Border is irregular or blurred

Color is not uniform

Diameter greater than 6 mm

Evolving changes from past appearance

Various types of melanoma are described as follows:

Superficial spreading:

It is most common on the trunk and on the legs and commonly seen in 30-50 year olds. It typically is a flat or barely elevated brownish lesion with inhomogeneous color. Histology reveals buckshot scatter of malignant melanocytes.

Nodular:

Also seen commonly on legs and trunk. Starts as a dark papule which may become a nodule and ulcerate. It can lack the pigment sometimes and appear skin colored (amelanotic nodular melanoma). It is often well rounded and homogeneously pigmented leading to delay in diagnosis. This is the only relatively common melanoma that does not show a radial growth phase.

Lentigo maligna:

Commonly seen on head, face, neck, shoulders and arms in elderly light skinned individuals. It has extremely slow growth and it can exist in the in-situ form for years before growing.

Acral lentiginouS:

This is relatively less common in whites but accounts for upto 2/3rds of melanoma cases in dark skinned populations. The diagnosis is often delayed and hence prognosis is relatively poor. As the name suggests it occurs on hands and soles. It can also occur in the nail bed.

Amelanotic:

These are uncommon and appear as flesh-colored lesions often confused with carcinomas. As mentioned above it most commonly occurs in nodular form.

Treatment for melanoma is primarily surgical although trials of Interferon alpha have been successful to some extent. The most important predictor of prognosis is the thickness at the time of diagnosis (Breslow Index).

Herpes labialis

Image from CDC public health image library

Herpes labialis or 'cold sore' is caused by Herpes simplex virus (HSV) type 1 which is a double-stranded, enveloped, DNA virus. Diagnosis is clinical. Treatment is symptomatic. Topical acyclovir may be helpful in recurrent cases.

Therapy for acne

Mild acne

Comedonal acne is especially responsive to topical retinoids. Salicylic acid is not as effective a comedolytic as retinoids.

For inflammatory acne, combination therapy is the mainstay of treatment. Topical retinoids (tretinoin Evidence , adapalene Evidence and tazarotene) are prescribed in combination with benzoyl peroxide Evidence and/or topical antibiotics (clindamycin Evidence or erythromycin Evidence).

Moderate acne

Moderate comedonal acne with minimal inflammation may respond to topical retinoids alone. Inflammatory acne is best treated by a combination of systemic antibiotic with topical retinoid. If this does not make acne better in 8-10 weeks, benzoyl peroxide should be considered. This is mainly to reduce production of antibiotic resistant strains but also increase the efficacy of the treatment.

Severe nodulocystic acne

For severe or nonresponsive acne, oral isotretinoin for 6 months should be considered. Systemic steroids can be used as an adjunct.

Pemphigus

Pemphigus is an autoimmune disorder of the skin and mucous membranes characterized by blisters associated with the binding of IgG autoantibodies to epithelial cell surface. The common form is called Pemphigus vulgaris. Antigens in pemphigus are believed to be desmoglein 1 and desmoglein 3. Antibodies belong to IgG1 and IgG4 type.

Mean age of onset is approximately 50-60 years. Histologic changes consist of intercellular edema with loss of intercellular attachments in the basal layer. Suprabasal epidermal cells separate from the basal cells to form clefts and blisters. These findings can help differentiate phemphigus vulgaris from pemphigus foliaceous, which demonstrates a more superficial epidermal cleavage.

Koilonychia - Spoon shaped nails

Koilonychia is relatively more frequent in children and usually resolves with aging.

When in doubt the diagnosis can be confirmed by keeping a drop of water on the nail. If the drop falls off koilonychia is unlikely.

Common causes include:

Iron deficiency anemia
Diabetes mellitus
Protein malnutrition
SLE
Raynaud's disease and phenomena

Diaper rash

Topical barriers in the form of ointments or pastes are considered first-line therapy for treating and preventing irritant diaper dermatitis (common diaper rash). Do not choose clotrimazole or any other antifungal agent as the treatment of choice in the USMLE unless the diagnosis is clearly fungal.

Quiz

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?Ans: Gottron's Paplues seen in Dermatomyositis

Quiz

What is the diagnosis?

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Ans: Waardenberg syndrome. Note the heterochromia irides, white forelock and hypertelorism. There is sensori-neural hearing loss in this condition.

Quiz

6-year-old boy developed disseminated red papules, vesicles and crusted vesicles after 3 days of fever.

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Diagnosis: Chicken Pox (Varicella). Note the polymorphic rash with lesions in different stages of development

Neonatal Pustular Melanosis

A healthy 5-day-old boy presents with symmetric widespread hyperpigmented facial macules and pustules. The diagnosis is Neonatal Pustular Melanosis. It is a benign condition and much more common in African American Population.