Lawrence S. Neinstein, M.D., F.A.C.P.
Professor of Pediatrics and Medicine
USC Keck School of Medicine
Executive Director
University Park Health Center
Associate Dean of Student Affairs



Medical Problems - Dermatology - Miscellaneous Dermatology Lesions (B4)

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pseudo folliculitis barbae
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This condition is pseudo folliculitis barbae. These are papulopustular lesions that are right next to the hair follicles. Pseudofolliculitis barbae is a noninfectious, inflammatory condition usually occurring in males with curly hair. It is caused by the reentry of curved hairs after shaving. While growing a beard will cure this condition, this is not what most teens chose to do. Improvement can occur with some of the following tips:

  • Soften facial hair well with warm water before shaving.
  • The bearded area should be covered with gentle shaving gel before shaving.
  • A special razor can be used and include razors such as the Bump Fighter, the Foil Guard shaver and the PFB razor.
  • A soft-bristled toothbrush can be used in a circular motion on bearded area to dislodge hair tips. This can be done twice a day, before shaving in am and at bedtime.
  • Teen should shave in the direction of beard growth not against.
  • Aftershave lotion should be avoided.
  • Teen can use very mild steroid lotion for very brief period of time. Steroids on face can lead to skin color changes and atrophy.
  • Topical retinoids are sometimes helpful.

Several skin eruptions are common in the groin area of teens. The first is tinea cruris.

tinea cruris
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This is a fungal infection caused by a dermatophyte. It can be pruritic and is treated with topical antifungals. This lesions has a sharp border and central clearing. The lesion below can look similar in the groin, however it has no central clearing. The lesion is shown with and without a Wood's light exam.

fungal infection caused by a dermatophyte
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fungal infection caused by a dermatophyte - wood's light
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This is erythasma, a superficial bacterial skin infection of intertriginous sites caused by Corynebacterium minutissiumum (short gram-positive diphtheroid). It particular the rash fluoresces a coral red color under a Wood's lamp caused by porphyrin production. A potassium hydroxide preparation may show negative results, but Gram's stain may show Gram-positive filamentous rods (Corynebacterium minutissimum). Treatment is with erythromycin.

Another rash that can occur in the groin is candida. Here is a typical candida infection in an intertriginous area. It is characterized by no sharp border, no central clearing and satellite lesions.

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The next two slides are from teens with acanthosis nigracans.

acanthosis nigracans
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acanthosis nigracans
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It is associated with obesity and with insulin resistance. One should screen for diabetes in an obese teen with this condition or with a teen with this condition and family history of diabetes. A fasting blood glucose would be a good initial screen.

Acanthosis nigricans usually appears as a gray-brown thickening of the skin. The lesions are symmetrical, velvety, papulomatous plaques, with increased skinfold markings. They are commonly located on the base of the neck axilla, groin, and antecubital fossa. Occasionally, a parent is concerned as to why the teen does not wash themselves.

While in adults acanthosis can suggest a malignancy, the vast majority of acanthosis nigricans lesions in adolescents are not associated with a malignancy and are usually secondary to insulin resistance related to obesity. Weight reduction can reduce these lesions, otherwise the condition is difficult to treat. Lactic acid or alpha-hydroxyacid containing emollients, and tretinoin have been tried but without any controlled studies demonstrating efficacy.

pink pearly penile papules
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The following is an extremely important condition to be familiar with in teens.

These are on the corona of the penis and they are called " pink pearly penile papules ". I like to call them "PPP on the pp". They are a normal occurrence in about 15% of postpubertal males. The lesions are elongated papillae, about 1 to 3 mm in diameter, located on the coronal margin of the penis, especially the anterior border. They often appear in one to five rows and are usually of uniform size and shape. The color tends to be pearly white. They have a normal epidermal appearance microscopically. No treatment is necessary for this condition except reassurance. In distinction from these lesions, condylomata acuminata tend to be of less uniform size and shape, change over time, and are not neatly arranged around the corona of the penis.

Below is an example of keloid formation. Some individuals heal with significant fibrosis tissue formation. A common location is in the earlobe after pierced ears.

keloid formation
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Below is an example of cholinergic urticaria .

cholinergic urticaria
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Cholinergic urticaria: This reaction can be triggered by heat, exercise, or stress caused by a reaction of acetylcholine on the mast cell. Clinically, the teen will develop highly pruritic, punctate wheals 1-3 mm in diameter which are surrounded by large areas of erythema. The palms and soles are always spared. Antihistamines can help with this problem.

Below are two wrist lesions that might look similar. However, the lesion on the left is a reaction to a nickel band which is quite common. The lesions on the right are self inflicted cigarette burns. In an individual with self inflicted injuries such as this, it is critical to ask about a prior history of sexual abuse or physical abuse.

Adolescents may come in with concerns about findings that might be normal but they have some concerns that this might be a tumor or an STD. One example was the pink pearly penile papules. This is another example. This is normal glandular tissue of the scrotum.

normal glandular tissue of the scrotum
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Copyright (©) 2004-2013 Lawrence S. Neinstein, University of Southern California . All rights reserved. Republication or redistribution of the text, table, graphs and photos is expressly prohibited. The University of Southern California shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon.