Idiopathic guttate hypomelanosis
Alerts and Notices
SynopsisIdiopathic guttate hypomelanosis (IGH) is a common acquired condition, characterized by scattered 3- to 5-mm hypopigmented macules occurring on chronically sun-exposed skin. IGH typically occurs in middle-aged individuals with photodamage and increases in incidence with age and continued sun exposure.
While the exact cause is unknown, IGH has been hypothesized to be ultraviolet (UV) induced. Other contributing factors that have been suggested include aging, trauma, genetic factors, and autoimmunity.
While IGH occurs more commonly in lighter skin phototypes, it does occur in all skin colors, and it appears more prominent in individuals with darker skin.
L81.9 – Disorder of pigmentation, unspecified
1717003 – Idiopathic guttate hypomelanosis
Differential Diagnosis & Pitfalls
- Hypopigmented flat warts – These are perceptibly raised.
- Hypopigmented seborrheic keratoses – Also perceptibly raised.
- Tinea versicolor – Typically scaly and limited to the upper trunk and shoulder.
- Pityriasis alba – Usually seen in atopic children; lesions are ill-defined.
- Pityriasis lichenoides chronica (PLC) – Usually seen in a younger patient population than IGH and found on sun-protected skin; in young patients with dark skin phototypes, PLC may present as hypopigmented macules, and PLC may resolve with guttate leukoderma.
- Leukodermic macules of Darier disease.
- Postinflammatory hypopigmentation – Can be distinguished by preceding history of dermatitis.
- Vitiligo – Lesions are depigmented, often acral, and coalesce to form larger depigmented patches.
- Leukoderma punctata – 0.5- to 1.5-mm achromic macules that follow psoralen plus UVA (PUVA) or UVB therapy.
- Lichen sclerosus – Shows a "tissue paper" atrophic appearance with telangiectasia; not confined to sun-exposed skin.
- Atrophie blanche – Favors the distal shins and ankles but is usually atrophic and surrounded by telangiectasia.
Patient Information for Idiopathic guttate hypomelanosis
OverviewIdiopathic guttate hypomelanosis is a very common, harmless skin condition in which small, smooth, white spots appear on the legs, arms, back, and sometimes on the face. The spots are a lack of pigmentation or absence of coloration. The cause is uncertain, but it may be related to sun exposure. Aging increases the number of spots, but doesn't increase the size of the spots.
Who’s At RiskAdults over age 40 with lighter skin types and a history of frequent sun exposure are the most at risk. Idiopathic guttate hypomelanosis may occur in families.
Signs & SymptomsLook for speckled or confetti-like round or oval white spots symmetrically distributed over tanned legs and arms, and sometimes on the upper back. Later, spots may also appear on the face or other sun-exposed areas of skin.
Self-Care GuidelinesSince sun exposure is believed to trigger the white spots of idiopathic guttate hypomelanosis, it is best to avoid sun exposure, avoid tanning beds, use sunscreen, and cover up with protective clothing.
When to Seek Medical CareConsult your health care provider when you observe skin changes that may concern you, and describe any additional symptoms you may have.
TreatmentsYour health care provider may perform a biopsy to rule out malignancy or other severe skin conditions.
For cosmetic reasons, you may be prescribed topical steroids or topical retinoid creams. Other treatments include laser therapy (fractional carbon dioxide laser) and liquid nitrogen cryotherapy (freezing). You will need to discuss with your doctor the advantages and possible side effects of each treatment.
Idiopathic guttate hypomelanosis