What Causes Post-Inflammatory Hypopigmentation?

Patient Presentation
A 7-year-old Asian female came to clinic because of diffuse white spots on her elbows, upper arms, legs and neck. Her mother had noticed them for about 2 months and they were getting worse over the summertime, because they were getting whiter. They had not tried any treatment including medications. They denied any new soaps, lotions, detergents, insect repellents, etc. There were no exposures to animals including dogs or farm animals and they had not traveled out of the immediate area. She had been outside at several day camps and spent other days at the swimming pool. She sometimes wore sunscreen but it was a new bottle and of the same brand she had previously used. The past medical history was positive for atopic dermatitis. The family history was positive for atopic dermatitis and seasonal allergic rhinitis.

The pertinent physical exam showed a healthy female with normal vital signs and growth parameters. Her examination was normal except for her skin. She looked tanned overall. She had diffuse lighter areas on the extensor areas of her lower and upper arms, outer thighs, and neck/upper back. She had similar lesions on her central cheeks. They were not punched out/demarcated and there was no scale. There was general xerosis is the same areas.

The diagnosis of post-inflammatory hypopigmentation was made. The patient and parent confirmed that the same areas were her “bad” areas of atopic dermatitis. She also said that she was itchy at times and had been scratching the areas also occasionally over the summer. The natural history was explained to the family, along with instructions on consistent and frequent sunscreen and emollient use.

Discussion
Hypopigmentation can be worrisome for many families because of cosmesis and the worry that “something is wrong.” The normal natural changes in skin-tone over the year due to different light exposure and wide variations within individuals is not something that many people are aware of.
Post-inflammatory hypopigmentation is a common cause of hypopigmentation. Vitiligo is the most common cause of depigmentation.

Vitiligo is an acquired, depigmenting disorder with typical lesions appearing as milky white macules with distinct margins that are not scaly. Hair (including eyebrows and eyelashes) can be depigmented if it occurs in a particular area. It occurs in about 0.5-1% of the population and is the most common cause of depigmentation. Melanocytes are absent from the affected skin area. All ages and genders are affected. Vitiligo usually is of the non-segmental form where lesions are bilateral and symmetrical across the body. The segmental form is unilateral, band or segmental in distribution. The lesions can occur in any part of the body and for some people they are increased because of skin trauma (clothing constrictions in certain areas, i.e. Koebner phenomenon)

Vitiligo has been known for centuries and social discrimination because of the white lesions has been intense at different times and in different cultures. Vitiligo was often confused with leprosy for instance in the past, leading to social stigma based similarities between the white skin lesions. Even today there is higher social stigma for patients whose vitiligo lesions are visible versus not visible. Patients need general social support and may need professional counseling as part of their treatment. Treatments include using topical corticosteroids or calcineurin inhibitors as a first line treatment usually for at least 6 months to be able to view results. Phototherapy with UVA and UVB can also be used for at least for 3-6 months to view results. Other more invasive treatments potentially include surgery such as grafts or depigmenting treatments.

Other causes of hypopigmentation include:

  • Vitiligo – most common depigmentation disease
  • Endocrine – Cushing’s syndrome, hypopituitarism
  • Incontientia pigmenti
  • Hypomelanosis of Ito
  • Halo nevus
  • Hypomelanosis – idiopathic guttate
  • Leukoderma – chemical or drugs, puncta
  • Normal – fair skin-tone individual
  • Nutrition – kwashiokor
  • Post-inflammatory hypopigmentation
  • Pityriasis alba
  • Piebaldism

Learning Point
Post inflammatory hypopigmentation is very common. It can be localized or diffuse, but is more prominent in darker skin-toned individuals. “Melanocytes can react with normal, increased or decreased melanin production in response to cutaneous inflammation or trauma. The chromatic tendency is genetically determined, and inherited in an autosomal dominant pattern. People with weak melanocytes, which have high susceptibility to damage, are more likely to develop hyperpigmentation, whereas those with strong melanocytes develop hypopigmentation.” The areas affected usually correspond to the original areas of inflammation. Wood’s lamp examination highlights the lesions. Treatment is identification of the cause and preventing recurrence (the most important part), steroid creams along with tar preparation, calcineurin inhibitors, and sun or UV exposure are also options.

Causes of post-inflammatory hypopigmentation include:

  • Skin inflammation
    • Atopic dermatitis
    • Contact dermatitis
    • Graft vs host reaction
    • Hypopigmented mycosis fungoides
    • Insect bites
    • Lichen planus
    • Lichen striatus
    • Lichen sclerosis et atrophicus, extragenital
    • Lupus erythematosus
    • Paget’s disease, extramammary
    • Psoriasis
    • Sarcoidosis
    • Scleroderma
    • Stevens-Johnson syndrome
  • Infections
    • Herpes zoster
    • Impetigo
    • Leprosy
    • Onchocerciasis
    • Pityriasis versicolor
    • Syphilis
    • Varicella
  • Medical interventions
    • medications – corticosteroid
    • Chemical peels
    • Cryotherapy
    • Dermabrasion
    • Laser treatment
  • Other
    • Burns

Questions for Further Discussion
1. What causes hyperpigmentation?
2. What are indications for referral to a dermatologist?
3. What causes albinism?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Skin Pigmentation Disorders

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Vachiramon V, Thadanipon K. Postinflammatory hypopigmentation. Clin Exp Dermatol. 2011 Oct;36(7):708-14.

Bodemer C. Incontinentia pigmenti and hypomelanosis of Ito. Handb Clin Neurol. 2013;111:341-7.

Nicolaidou E, Katsambas AD. Pigmentation disorders: hyperpigmentation and hypopigmentation. Clin Dermatol. 2014 Jan-Feb;32(1):66-72.

Ezzedine K, Eleftheriadou V, Whitton M, van Geel N. Vitiligo. Lancet. 2015 Jul 4;386(9988):74-84.

Roh MR, Oh SH. Acquired hypopigmentation disorders other than vitiligo. UpToDate. (rev. 1/17/18, cited 9/18/18y).

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa